'By the Senate '
Option: C
Explanation:
The President can make appointments by and with the advice and approval of the Senate i.e., the PAS points, at the top levels of the federal administration. According to 'Article II', 'Section 2', 'Clause 2' of the US Constitution’s Appointments Clause, the President has the power to nominate and appoint any public officials with the confirmation of the Senate. But the Senate has to take certain principal officers such as cabinet secretaries, federal judges and ambassadors’ confirmation before approving.