Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
“Hyper-catabolism, of course. I thought it might be. How long since you had your last rejuvenation? And who gave it?” “About ten years ago,” Giles the horror of being the first! neither did he anticipate By LESTER DEL REY answered. He found his identity Illustrated by JOHNS were returning the pulse in his neck was pounding and his the doctor studied it. “My sixteenth.” It wasn’t going right. He could of his this year—and Harry. Maybe he’d even tell Harry the truth, once they got heart hammering in his chest. He’d been a fool to come to work, he realized. But with the Procyon when he stopped to think of it. any trouble, Doctor. I was one of the first million cases, when a lot of people couldn’t rejuvenate —LESTER DEL REY at all, and I had no trouble even was no telling what might turn up. Besides, that fool of a medicist shuttle arriving yesterday, there her, refilling the cup. She’d made the coffee stronger than usual diagnosed at the time, or even a fault in the treatment. That’s better than he knew himself—which wouldn’t be hard, he was more important. It hadn’t been a joke about his growing old, after all. But now, in a few days, he’d be his old—no, of course not—his young self again! thought. He’d hardly recognized the stranger in the mirror as he Even his hair had seemed thinner, though that, of course, was He’d been driven to it, he knew, He resented every second of it. It was as if the almost forgotten specter of age stood beside him, counting the seconds. But at last they were through and he was led into the quiet rejuvenation room, where the clamps were adjusted as he watched the man’s amazed brain-wave pattern. It had been nothing like this his first time. Then it had required months of mental training, followed by crude mechanical and the first suspicion of his trouble, “I’m all right!” he told her something inside him had been themselves, with the brain as only a linkage to it. They’d discovered that, and the fact that the mind could effect physical changes in the body. Even such things as forcing him to make this decision. operate. There had been impossible faith cures for millenia—cataracts removed from blinded eyes within minutes, even—but finding the mechanism in the brain that worked those miracles had taken an incredible amount of study and finding a means of bringing it under control had taken even longer. Scientists there had puzzled over it, reset it and sent it back. The Now they did it with dozens of mechanical aids in addition to the hypnotic instructions—and did it usually in a single sitting, with the full transformation of the body taking less than a week inside while he drank another coffee, and finally pulled message that had come on the shuttle. He fingered the microstrip He came out of it without even a headache, while they were removing the probes, but the with the eternal unconscious passed the drastic birth limitation act and his mother had spoiled him. He’d even tried to expectation that he would find himself suddenly young had been born just before Earth again. But that, of course, was ridiculous. It took days for the mind an injection of some kind and another sample of his blood was taken, while the earlier tests were repeated. But finally the doctor nodded. carried a glowing account of drive working, there was no reason he should give up his work. The discovery that men could the discovery of the super-light missile and what it might mean. live practically forever had put an end to most family ties when it had been covered and recovered, he could still sense the glances of the others, as if he were Vincenti in one of the man’s because of special ability—and patience was still foreign to He gave it up and went to bed—to but he’d heard them all before, except for one about the night’s sleep after a little relaxation. Even that failed him, though. He’d developed one of the finest chess collections in the world, but world made in two centuries the young men were sent out as soon as no real progress had been he’d developed through new thinking. There was a measure of truth in it, unfortunately. the years helped to add to the richness of living now. his old answers. “We’re still ahead in medicine and we’ll get the other discoveries eventually, without drive works! That missile or other. Could they really dwindle down? Suppose he couldn’t rejuvenate all the way? He knew been fifty when he finally learned how to work with the doctors and they could only bring him back to reached Sirius in less than ten days. We can have the secret of reduce the slice of eternity that rejuvenation meant? And what had happened to Sol? Or suppose it wasn’t rejuvenation, after all suppose something about thirty, instead of the normal had gone wrong with him He fought that off, but he couldn’t escape the nagging doubts at the doctor’s words. this antigravity in less than a the speaker. “Of course not! It took two accidents to get the thing back to us—and with a ” Jordan’s voice rattled permanently? were still there and the circles under his eyes. He searched for at the doctor’s office and he could find no new ones. power to rejuvenate. We can’t put human pilots into a ship with our drive until we’ve tested it more long it had been. Nor why. “In the spring, a young man’s fancy,” he quoted to himself, and then shuddered. It hadn’t been that kind of spring for him—not this rejuvenation nor the last, nor the one himself and partially succeeded, until he reached the doctor’s office. Then it was no longer necessary to frighten himself. The wrongness was too strong, no matter the doctor’s technical jargon. Now that he knew there was reason for his fear, it seemed to numbed him. “I’d rather know the whole truth,” he said. His voice sounded dead in his ears. “The worst first. The rejuvenation...?” Cobb sighed and yet seemed relieved. “Failed.” He stopped, and He looked sick, for he had no answer. NO SANE man would risk a to help. He felt choked, imprisoned, somehow lost he’d been twisting. Then he was staring unbelievingly knowledge is still on record. We can fix the heart and all the rest. You’ll be in good physical condition, better than your grandfather—” pronounce the words. He’d grown old and he’d grow older. And eventually he’d die! An immortal man had suddenly stop twice to catch his breath and fight against the pain that said, and was surprised to find he meant it. The man had done all he could and had at least saved him the suspense of growing doubt and horrible eventual discovery. it was still possible to find personal servants. Now he managed Even his car would outlast him. He climbed into it, still partly numbed, and began driving mechanically, no longer wondering about the dangers that might possibly alcohol combined with the reaction from his panic to leave him almost himself again. After all, there was nothing to worry about Earth’s doctors could cure anything. “I guess you’d better call Dr. Vincenti,” he decided. Vincenti Vincenti isn’t with us, sir. He Vincenti had been an oddly grin and somehow the right words came to his lips. “I saw the doctor, he told her. “They tell me I’m just growing old.” as so many others had, for even with modern safety measures Just how bad did he look? Well, he’d soon find out. with all the degrees Dr. Cobb had picked up in some three hundred Dr. Vincenti had received an invitation Or had he even been one of those to whom the same report had been delivered by some doctor? It didn’t matter, but it would explain things, at least. Those dwindling years had the doctor began working on it. been precious once. He unexpectedly “Your friend told me about the recalled his own grandfather holding him on an old He inspected it and began making tests. Some were older than Giles could remember—knee reflex, blood pressure, pulse

<question>:
What is likely the reason that Dr. Vincenti left Earth?

<options>:
A he missed his family and wanted to live with them
B he wanted to share his newest discovery with a different planet
C there wasn't a lot of demand for doctors on Earth
D he discovered the truth about rejuvenation

<answer>:

D