Why Are Elections in the United States Called "First Past

Why are elections in the United States called "first past the post"?

A) It means that the person with the most votes, not necessarily a majority, wins the election.
B) It means that elections in the United States are hard to predict, like horseracing.
C) It means that the person with the majority of votes wins, unless it is the presidential election.
D) It means that the post (the electoral college) is the only determinant for elections in the United States.
E) It means that, like horseracing, elections take place quickly in the United States as opposed to other democratic nations.