The correct answer is D. forbidden.
To proscribe something means to forbid it. In this case, the physician has forbidden the patient from eating a non-vegetarian diet. This could be for a number of reasons, such as the patient’s health condition or religious beliefs.
The other options are incorrect because they do not accurately reflect the meaning of the word “proscribe.” Option A, recommended, means to suggest or advise something. Option B, allowed, means to give permission for something to happen. Option C, increased, means to make something larger or greater.
It is important to be able to understand the meaning of words in order to comprehend the meaning of sentences. The word “proscribe” is a relatively uncommon word, but it is important to know its meaning in order to understand the sentence “His physician has proscribed non-vegetarian diet.”