What event triggers a contingent election for president?

A. One of the nominees doesn't win their state electoral votes
B. One of the nominees drops out of the race before Election Day
C. One of the nominees fails to receive a majority of electoral votes
D. One of the nominees switches to a different political party.

C. One of the nominees fails to receive a majority of electoral votes

In the United States, a contingent election for President is triggered if no candidate receives an absolute majority of votes in the Electoral College, which would be at least 270 out of 538. If this happens, the decision on who becomes the President is made by the House of Representatives, with each state delegation having one vote. Meanwhile, the Senate would choose the Vice President, with each senator having one vote. This procedure is outlined in the 12th Amendment to the U.S. Constitution.