My physician said that I ___ stick to a healthy diet if I want to be healthy.a) would ratherb) ratherc) had better tod) had better

To determine the correct answer for the sentence completion, we must analyze the options in the context of advice or recommendation.

1. Option Analysis:

   • a) “would rather” suggests a preference but does not imply strong advice.
   • b) “rather” alone lacks the grammatical structure needed here.
   • c) “had better to” is grammatically incorrect; “to” should not be included after “had better.”
   • d) “had better” is a commonly used phrase that implies strong advice or recommendation.

2. Correct Usage:

   • The phrase “had better” is properly used to advise someone on the right course of action, particularly when there may be negative consequences if one does not follow that advice.

Thus, the most appropriate choice for the sentence is:

Final Answer: d) had better.

So the complete sentence reads: "My physician said that I had better stick to a healthy diet if I want to be healthy."