Question

Who decided the 1824 presidential election, and why?
Voters decided it with a second vote because the first election resulted in a four-way tie.
Congress decided it because none of the four candidates received a majority of the votes in the election.
Andrew Jackson and John Quincy Adams agreed to serve as president and vice president, respectively, because Jackson received the most votes.
John Quincy Adams and Andrew Jackson agreed to serve as president and vice president, respectively, because Adams received the most votes.

Answer 1

Congress decided it — specifically the House of Representatives. None of the four candidates won a majority of the electoral votes, so under the 12th Amendment the House chose the president (it selected John Quincy Adams).