Which of the following is true under the system of checks and balances?

a. The Supreme Court can remove members of Congress, and Congress can impeach the President.
b. A bill becomes law when the House and the Senate pass it, and the Supreme Court declares it constitutional.
c. The Senate must ratify treaties negotiated by the President before they become law.
d. The Supreme court can overrule the President's policy proposals.
e. House of Representatives appoints justices to the Supreme Court & the Senate approves the appointments.