Which of the Following Is True of the Twenty-Fifth Amendment

Which of the following is true of the Twenty-Fifth Amendment?

A) It was first used when President Ford nominated Nelson Rockefeller as vice president.
B) It has never been used.
C) It was the result of the long illness of President Carter.
D) It is only used when the Constitution explicitly says that it is applicable.
E) It was used by President Nixon when he appointed Gerald Ford vice president.