John C. Calhoun is best described as

A. a two-time vice president who supported slavery and states' rights.

B. a Massachusetts senator who was antislavery but supported compromise.

C. a president who declared that nullification was a form of treason.,

Calhoun was Vice President under the administration of John Quincy Adams, and stayed on with Andrew Jackson after Adam was defeated during the election of 1828. A native of South Carolina, Calhoun was known for being a strong proponent of slavery in the South. As such, the best answer would be A. "A two-time vice president who supported slavery and states' rights".