Federal judges are
a) nominated by the president.
b) confirmed by the u. s. senate.
c) appointed for an indefinite period, providing they maintain "good behavior."
d) all of these: nominated by the president, confirmed by the u. s. senate, and appointed for an indefinite period providing they maintain "good behavior."
e) none of these answers is correct.

d) all of these: nominated by the president, confirmed by the U.S. Senate, and appointed for an indefinite period providing they maintain "good behavior."

Explanation:

Federal judges, who are the ones that are that preside over the Supreme Court proceedings and evaluate laws, are indeed nominated by the President, by the U.S. Senate, and appointed for an indefinite period providing they maintain "good behavior" or until they decide to retain, as Article II, Section 2 of the U.S. Constitution provides:

he (The President) shall nominate, and by and with the advice and consent of the Senate, shall appoint ambassadors, other public ministers and consuls, judges of the Supreme Court, and all other officers of the United States.

And as Article III, Section 1 of the U.S. Constitution states:

The judges, both of the supreme and inferior courts, shall hold their offices during good behavior

With this latter provision, the Constitution guarantees that judges make decisions and evaluate statutes according to what is right under the law, and not according to popular's opinion or political pressure. This way, judges don’t have to fear that they will be fired if they make an unpopular decision.