Answer:
C. Congress must interview and approve the nominee with a majority vote.
Step-by-step explanation:
Section 2 of Amendment 25 says "Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress."
This means that if there is a need to change vice president, before the term ends. The president must nominate someone he believes to be able to occupy the position. The nominated person will be put to the vote at the congress, which must interview and approve the candidate with the majority of votes.