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

<passage>:
"These donors were dead, but you can be thankful we had parts of their brains available." Crander delved into the file and came up with a mind in a sound body, but Dan Merrol had too much of one—and also too much of the other! "Sorry, darling," said Erica. She yawned, added, "I've tried—but I just can't believe you're my husband." He felt his own yawn slip off his face. "What do you mean? What am I sat up. "They said you were Dan Merrol at the hospital, but they must "My name is Dan Merrol." "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 felt like Dan Merrol. "Your name is Erica." "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. 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 of him to have mentioned them. No woman approves her predecessors. "That's six. Where do I come in?" "Erica. You're the seventh and best." It was just too many, now that he thought of it, and it didn't seem right. She sighed and drew away. "That was a lucky guess on your age." He had been seriously injured and he was still weak from the shock. He got up and walked unsteadily to the mirror. "Now what?" "Stand beside it. Do you see the line?" Erica pointed to the glass. memory? He leaned against the wall and nearly fell down. The length of that arm was unexpectedly different. He hobbled over to a chair and sat down, staring miserably at Erica as she began dressing. There was quite a contrast between the loveliness of her body and the circus comedy of his own. the last snap, which took considerable effort. She was a small girl generally, though not around the chest. It was difficult and in addition to his physique there were the and all those wives too. Erica came close and leaned comfortingly against him, but he wasn't 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 had to do. The jacket he had worn last night didn't fit. Erica cut off the sleeve in it, he managed to expand it so it was not too tight. The trousers were also a problem—six inches short with no material to add on, but here again Erica proved equal to the task and, using different . Erica gazed at him with melancholy affection. "I can't understand why they let you out wearing those clothes—or for that matter, why they let you out at all." 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 It was then he'd grabbed her, to keep her from talking to the hospital. She was looking at him, waiting for that explanation. He shook his mind frantically and the words came out. "Self-therapy," he said briskly. "The patient alone understands what he needs." She started to interrupt, but he shook his head and went on blithely. "That's the first corollary of the theorem. The second is that there are critical patient carefully." examined me last night, I was much stronger than they expected—so, "How much do you remember of the accident?" She shoved aside her own accident "It wasn't anybody's fault. The warning devices which were supposed to liner. They had assumed he was the pilot because of where he was found, passionate, petite and wild, casual and complaisant, nagging and insecure? Erica he didn't remember at all, save from last night, and what was that due to? "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 his chair and looked at her uncertainly. "Let me call a 'copter," she said. "I hate to see you go." "Wysocki's theorem," he told her. "The patient has decided to walk." He weaved toward the door and twisted the knob. He turned in time to catch her in his arms. "The director—Doctor Crander. I don't have an appointment." "Then the director can't see you." The girl looked up and her firmly one was far larger and clumsier, more suited to mayhem than music. "When can I see the director?" She blinked at him. "A patient?" She didn't need to look twice to see On his way in, he miscalculated, or she did, and he brushed against her. The touch was pleasant, but not thrilling. That reaction seemed reserved for Erica. "Glad to see you," said Doctor Crander, behind the desk. He was nervous and harassed for so early in the morning. "The receptionist didn't give hospital didn't seem to have a calming influence on either her or the doctor. "That's why I came here. I'm not sure who I am. I thought I was Dan Merrol." himself by wiping his forehead. "Our missing patient," he said, sighing The doctor came cautiously around the desk this time. "Of course. I recognize you immediately." He exhaled peevishly. "Where did you go? 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." began hauling out a variety of instruments with which he poked about his bewildered patient. He pressed the buzzer and an angular woman in her early forties answered. "Miss Jerrems, the Dan Merrol file." Miss Jerrems flashed a glance of open adoration at the doctor and before she could reel it in, her gaze swept past Dan, hesitated and pictures of the wreckage in which you were found—notice that you were strapped in your seat—as you were received into the hospital—at various stages in surgery and finally, some taken from the files of the taken just after your last operation. Both were corrected according The mass-cell radiographs did seem identical and Dr. Crander seemed certain. Taken altogether, the evidence was overwhelming. There had been no mistake—he was Dan Merrol, though it was not difficult to understand why Erica couldn't believe he was her husband. "You did a fine job," he said. Recalling the picture of the wreckage, he knew they had. "But couldn't you have done just a little better?" complaint...." "Nothing specific. But look at this hand...." The doctor seized it. "Beautiful, isn't it?" ?" cried the doctor. "Do you have any idea of the 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 replaced." Crander traced out five areas he could feel, but not see. "Samuel authentic, but they weren't his—nor did the other wives belong to him. It was no wonder Erica had cringed at their names.

<question>:
How did the hospital positively identify the patient from the accident?

<options>:
A His location during the crash
B Mass-cell radiographs
C Dental records
D Erica identified the patient

<answer>:

B