The growing extremism of the South: a. led militant Southerners to argue that the U. S. government had the power to protect slavery but not to regulate it. b. caused many Southerners to seriously consider emancipation over a period of twenty-five years. c. was tempered by John C. Calhoun's ambition to become president. d. was based upon a broad and flexible interpretation of the Constitution.

d. was based upon a broad and flexible interpretation of the Constitution.

Explanation:

The South were heavy proponents of slavery and they resented the Federal government's efforts to reduce its occurrence. This feeling of discontent kept growing until it became quite extremist.

These extremists felt that the Federal government should not be able to impede upon the rights of states and so favored a broad and flexible interpretation of the Constitution that would support their rights as states and make them get away with slavery.

right the disagreed with the three-fifths compromise.