Which of the following best describes the Wilmot Proviso?

Which of the following best describes the Wilmot Proviso?
a. The Wilmot Proviso was a document about the future of slavery in all territory acquired from b Mexico.
b. The Wilmot Proviso was an outline of the procedures for new territories to become states.
c. The Wilmot Proviso was a military strategy that explained how to win the Mexican-American War.
d. The Wilmot Proviso was a campaign document to help elect Congressman David Wilmot.