Mark the letter A, B, C, or D on your answer sheet to indicate the cor

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.    

John used to be one of the most ________ athletes in my country.

• A. A. succeed
• B. B. success
• C. C. successful
• D. D. successfully

Cấu trúc so sánh nhất (the most) => cần tính từ
=> C