What is a person appointed to vote in presidential elections for major candidates called?

The correct answer is "Elector." In the context of presidential elections, an elector is a member of the Electoral College, which is a body selected to elect the president and vice president of the United States. Each state is allocated a number of electors based on its representation in Congress, which corresponds to the total number of its senators and representatives.

When citizens cast their votes in presidential elections, they are actually voting for a slate of electors pledged to vote for their chosen candidate. This system is established by the U.S. Constitution and is designed to balance the influence of populous states against less populous states in presidential elections.

The other terms provided do not accurately describe this specific role. A voter refers generally to anyone who casts a ballot in an election; a delegate is typically associated with party conventions where they may represent their state's preferences in selecting a presidential nominee; and a representative usually pertains to someone elected to the legislative body, such as Congress. Therefore, "Elector" uniquely and specifically identifies the individuals who participate in the formal election of the president and vice president through the Electoral College system.