Congress Approves All Appointments to Federal Courts, but the Courts

Congress approves all appointments to federal courts, but the courts still provide a check on Congress. What power do the federal courts have over Congress?

A) They can decide the constitutionality of laws passed by Congress
B) They can impeach any member of Congress
C) The Supreme Court, with support from lower courts, can bar Congress from meeting
D) They appoint a new member if someone resigns