The correct choice is D.
The division of powers principle in the United States separates state authority into three branches: legislative, executive, and judicial. Furthermore, a system of Checks and Balances exists where each branch monitors the other two to stop any one branch from gaining excessive control.
Within this framework, the judicial branch holds judicial review authority, which empowers it to nullify laws and government actions enacted by the legislative and executive branches, respectively, if those actions are deemed unconstitutional.