Supreme Court & other federal court judges are nominated by the president & need to be approved by the Senate. This is an example of A. checks & balances
B. separation of powers
C. precedent
D. original jurisdiction

Checks and Balances

Explanation:

The president nominates all federal judges, who must then be approved by the Senate. The appointment of judges to lower federal courts is important because almost all federal cases end there. Through lower federal judicial appointments, a president “has the opportunity to influence the course of national affairs for a quarter of a century after he leaves office.” Once in office, federal judges can be removed only by impeachment and conviction.

A. checks and balances

Explanation:

In this question, the actions of one branch of government (Executive) has to be "approved" by another branch (Legislative). This is an example of checks and balances, where one branch of government regulates the activity or another to ensure fairness and avoid abuse of power.