When did john c. calhoun coin the phrase "state's rights"?

a when he tried to establish a confederation of states with authority over the national government

b in arguments about federal interference with southern states practing slavery.

c in a speech in which he argued against the establishment of a national bank

d when he fought for the "seperate but equal" clause established in plessy v. ferguson

The answer is:

B in arguments about federal interference with southern states practing slavery.

Explanation:      This a part of his ideas.

 "Our safety and prosperity depend on maintaining, in their full vigor, the restrictions imposed on the powers granted by the Constitution. So long as these are so maintained, and the powers confined to the objects intended by that sacred compact, we will be safe and prosperous,"

For him, states’ rights theory was not a vindication of local democracy, but a safeguard for the distinct interests of the Southern slaveholding minority.