What did the Wilmot Proviso stipulate? A. that slavery would be permitted in any territory acquired from Mexico after the war B.
that the citizens would vote to determine whether or not slavery would exist in any territory acquired from Mexico after the war C. that slavery would be prohibited in any territory acquired from Mexico after the war D. that the U.S. Congress would vote to determine whether or not slavery would exist in any territory acquired from Mexico after the war
Historians often rely on both primary and secondary sources when supporting an argument, since it's important to use secondary sources to put the argument in context, and primary sources in order to make an original point.