Which historical event best demonstrates the operation of checks and balances? a) the senate approved the appointment of clarence thomas to the supreme court. b) south carolina seceded from the union over the issues of slavery and states rights. c) president george washington used the army to suppress a tax rebellion by pennsylvania farmers. d) president dwight d. eisenhower sent federal troops to enforce the integration of public schools in little rock, arkansas.

Sorry to editorialize but at the outset I just need to say that this is a terribly constructed question.

The correct answer is A.

Checks and Balances refers to the design of the US Federal Government wherein each branch is responsible to other branches in addition to being reliant on other branches for particular actions.

A is an example of the US Senate acting in their advise and consent role on the Executive Branch's power of appointment, which is a check that the Senate has on the Executive branch.

A better example would be the rejection of Robert Bork as a SCOTUS nominee.

answer; /// (c) i believe that the correct answer is; ///full faith and credit.