Answer:
C) performing a specific task that thr doctor described, such as using a walker.
Step-by-step explanation:
i don't think the answer could be a because he can say that he understand and don't.
no for b because the reason for asking questions is to find out what is wrong, if he knew he wouldn't have to ask. and d is wrong because nodding his head doesn't mean that he understands.
C is the answer because by performing a task that the doctor said, it shows that you really understands.