Mark the letter A, B, C, or D on your answer sheet...

Câu hỏi: Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
While it is difficult for some people to change unhealthy habits, there are__________for exercising frequently and eating fewer fatty foods.

A. an excellent reason

B. excellent reasons

C. excellent to reason

D. much excellent reasons