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

<passage>:
mind in a sound body, but Dan Merrol had too much of one—and also too much of the other! doing here then?" "Can't you remember?" Her laughter tinkled as she pushed him away and sat up. "They said you were Dan Merrol at the hospital, but they must have been wrong." "Hospitals don't make that kind of mistake," he said with a certainty he didn't altogether feel. "But "Of course—a replacement. I told you it was a serious accident. They had to use whatever was handy." "They told you that at the hospital." They hadn't—he'd read it on the chart. But he had been alone in the room and the name had to be his, and anyway he "They told you that too." She was wrong again, but it was probably wiser not to tell her how he knew. No one had said anything to him in the hospital. He hadn't given them a chance. He had awakened in a room and hadn't wanted to be alone. He'd got up and read the chart and searched dizzily through the closet. Clothes were hanging there and he'd put them on and muttered her name to himself. He'd sat down to gain strength and after a while he'd walked out and no one had stopped him. It was night when he left the hospital and the next thing he remembered was her face as he looked through the door. Her name hadn't been on the chart nor her address and yet he had found her. That proved something, "You may have known someone else with that name. When were we married?" Maybe he should have stayed in the hospital. It would have been easier to convince her there. But he'd been frantic to get home. "It was quite a smashup," he said. "You'll have to expect some lapses." "Almost three months. But most of that time you were floating in gelatin in the regrowth tank, unconscious until yesterday." She leaned forward and caressed his cheek. "Everything seems wrong, no "And I have one brown eye and one green." "It's not just that, darling. Go over to the mirror." He had been seriously injured and he was still weak from the shock. He got up and walked unsteadily to the mirror. "Now what?" comforted. "I waited till I was sure. I didn't want to upset you." He wasn't as sure as she seemed to be now. Somehow, maybe he was still scrambled face, to the mismatched lumps and limbs and shapes that, stretching the term, currently formed his body. It was clear what he had to do. The jacket he had worn last night didn't fit. Erica cut off the sleeve stuffed it in the toe. He looked critically at himself in the mirror. Dressed, his total effect was better than he had dared hope it would be. True, he did look different they let you out wearing those clothes—or for that matter, why they It was the clothes, plus the brief glimpse of his face, which had made her think she recognized him when he came in. "They told me you'd have to have psychotherapy and I'd have to have orientation before I could see you. That's why I was so surprised when you rang the bell." coordination. She could have been terrified, might have resisted—but she hadn't. At that time, she must have half-believed he was Dan Merrol, still dangerously near the edges of post-regrowth shock. She was looking at him, waiting for that explanation. He shook his mind frantically and the words came out. "Self-therapy," he said and carry them through by himself, even though running a slight risk of physical complications." It ought to be new—he'd just invented it. "You know how rapidly medical practices change," he said quickly. "Anyway, when they examined me last night, I was much stronger than they expected—so, when I wanted to come home, they let me. It's their latest belief that initiative is more important than perfect health." "Strange," she muttered. "But you are very strong." She looked at him Dan again, whether it was himself or another person. For a brief time, bewildered and believed what he was saying. "I've got to go. I'm due back," he told her. "What are you going to do?" he asked, deliberately toying with the last bite of breakfast. It gave him time to think. "They said they'd identified everyone, living or dead, and I supposed went to other hospitals, you know, the ones located nearest where they fell." Even if he was sure, he didn't know whether he could tell her—and he "Wysocki's theorem," he told her. "The patient has decided to walk." reconciled. He swept along, gaining control of his muscles. He became aware that he was whizzing past everyone. but he learned to walk at a pedestrian pace. However poorly they'd matched his legs, they'd given him good ones. Last night, on an impulse, he'd left the hospital and now he had to go back. Had hospital didn't seem to have a calming influence on either her or the himself by wiping his forehead. "Our missing patient," he said, sighing with vast relief. "For a while I had visions of...." He then decided that visions were nothing a medical man should place much faith in. "Then I The doctor came cautiously around the desk this time. "Of course. I It seemed wiser to Dan not to tell him everything. "It was stuffy about an hour ago. We didn't think you could walk at all so soon, or we would have kept someone on duty through the night." They had underestimated him, but he didn't mind. Of course, he didn't know how a patient from the regrowth tanks was supposed to act. The doctor took his pulse. "Seems fine," he said, surprised. "Sit down—please sit down." his bewildered patient. Finally Crander seemed satisfied. "Excellent," he said. "If I didn't know better, I'd say you were almost fully recovered. A week ago, we considered removing you from the regrowth tank. Our decision to leave , thought Merrol. It was not wholly true—Crander didn't seem much affected. But he was a doctor and used to it. Furthermore, he probably had room for only one emotion at the moment—relief at the return of his patient. our prize case, Merrol. I've never heard of anyone else surviving such extensive surgery. Naturally, we have a step-by-step account of everything we did." body, excepting the blood, constitute proof more positive than fingerprints before the surgical exchange of limbs. Don't ask me the next, and this test detects the difference." The mass-cell radiographs did seem identical and Dr. Crander seemed The doctor seized it. "Beautiful, isn't it?" "Perhaps—taken by itself." Dan rolled up his sleeve. "See how it joins that will smooth out as I exercise—but I'd like them the same length." "There were many others injured at the same time, you know—and you were one of the last to be extricated from the ship. Normally, when we have to replace a whole arm, we do so at the shoulder for obvious reasons. But the previously treated victims had depleted our supplies. permit you to die—there wasn't time to send to other hospitals. In fact there wasn't any time at all—we actually thought you were dead, but soon found we were wrong." Crander stared at a crack in the ceiling. "Further recovery will take other operations and your nervous system isn't up to it." He shook his learned the essentials. He was Dan Merrol and there was nothing they could do for him until it was too late. How long could he expect Erica to wait? The doctor hadn't finished the medical session. "Replacement of body parts is easy, after all. The big trouble came when we went into the brain." from shock. In addition, other sectors were damaged and had to be replaced." Crander traced out five areas he could feel, but not see. "Samuel

<question>:
Why did the doctors let Dan leave the hospital?

<options>:
A They did not, he left in secret
B They were following Wysocki's theorem
C They ran out of space for patients because of the accident
D They believed he was fully recovered

<answer>:

A