Which of the following is an example of separation of powers?

ASome government powers belong only to the national government, some only to the state governments, some are shared, and some are denied to both.

BCongress has the power to introduce and pass laws while the president has the responsibility of enforcing all federal laws.

CThe legislative branch (Congress) can pass laws, the executive (president) can veto laws, and the judiciary (Supreme Court) can find laws unconstitutional.

Dnone of these are examples of separation of powers