What action did the u. s. congress take as part of the isolationist trend that followed world war i?

It refused to ratify the Treaty of Versailles or join the League of Nations.

b is the answer i am assuming

interest groups send representatives to state capitals and to washington, d.c. to put pressure on members of congress and other policymakers. they engage in lobbying, or the organized process of influencing legislation or policy. lobbying can take many forms. interest groups can testify in congressional hearings.