Congressman Gerald Ford had become vice president of the United States when a. Nelson Rockefeller resigned the vice presidency to become governor of New York. Selected:b. Spiro Agnew resigned on corruption charges and Nixon appointed Ford under the Twenty-Fifth Amendment. This answer is incorrect. c. he was selected to replace Spiro Agnew as Nixon's vice president in the 1972 campaign. d. Nixon was impeached and Congress needed to select a new president. This is the correct answer. e. the Twenty-Fifth Amendment made the Speaker of the House vice president in case of potential impeachment.