According to William Riker, what is the commonality found across many cases of federalism?

Q. According to William Riker, what is the commonality found across many cases of federalism?

A.            It is the result of bargaining by foreign powers as they impose a political system on a territory

B.            It is the result of a bargain among regional actors and a prospective national government that is driven by external threats

C.            It is a result of territorial bargaining by elite powers as they develop a national system in a region

D.            This is a trick question: Riker identifies no such commonality, declaring that “all cases are perfectly unique.”

Answer: It is the result of a bargain among regional actors and a prospective national government that is driven by external threats