B) He is interested in designing machines that help people with disabilities.
EXPLANATION:
Since he is keen on planning machines that assist individuals with inabilities. Turning into a biomedical designer is one of his decision and most likely he was roused by individuals with inabilities as a result of his energy in composing moreover. With the goal for him to encourage these individuals, he chose to end up a biomedical specialist to make advancements to diminish the weight of these individuals.
The answer is letter B. because he is interested in designing machines that help people with disabilities. Becoming a biomedical engineer is one of his choice and probably he was inspired by people with disabilities because of his passion in writing also. In order for him to help these people, he decided to become a biomedical engineer to create technologies to lessen the burden of these people.
I think that the best phrase to fit into the blank is a "scientific theory".
A scientific theory is developed through experiments which use the scientific method, and a theory can be improved if additional data is available or if people provide suggestions which make the theory fit the data better.
