Refer to the passage below and then answer the question afterwards in the same language as the passage:

Passage: Most of the questions on the SAT, except for the optional essay and the grid-in math responses, are multiple choice; all multiple-choice questions have four answer choices, one of which is correct. Thirteen of the questions on the math portion of the SAT (about 22% of all the math questions) are not multiple choice. They instead require the test taker to bubble in a number in a four-column grid.

Question: how many answer choices does the multiple-choice questions have?
four