The correct answer is:
C) power to confirm appointments of federal judges.
The Senate has the authority to confirm or reject presidential appointments for federal judges, which includes Supreme Court justices. The other options do not accurately reflect the powers of the Senate.
- The power to file articles of impeachment is held by the House of Representatives.
- The power to confirm appointments of state judges typically falls under state legislatures or governors, not the Senate.
- The power to appoint ambassadors belongs to the President, although the Senate must confirm these appointments.