Why Is James Monroe's Presidency Known as the Era of Good

Why is James Monroe's presidency known as the Era of Good Feelings?

A) The United States experienced reduced levels of partisan conflict during this presidential administration.
B) The United States had just won a decisive military victory over Great Britain that ended that nation's dominance as a world power.
C) The United States finally removed all European rivals from what are now its present Atlantic to Pacific boundaries.
D) The United States prevented the expansion of slavery to its territories west of the Mississippi River.