What is the constitutionally established group of electors that select the president?

The correct answer is the Electoral College. This is the institution established by the United States Constitution for the purpose of electing the president and vice president. Each state is allocated a number of electors based on its representation in Congress, which includes both Senate and House members. During the presidential election, when citizens cast their votes, they are actually voting for a slate of electors pledged to support a particular candidate. These electors then officially cast their votes for president and vice president.

The function of the Electoral College reflects the federal nature of the United States government, balancing the influence of populous states with less populous ones in presidential elections. This system has been subject to much debate and discussion regarding its fairness and effectiveness, but it remains the method by which the U.S. elects its president.