Which of the following does not reflect the theory of checks and balance in the U.S. Constitution?

Presidential vetoes over congressional bills, Senate confirmation of presidential appointments and treaties, and judicial review of legislation by the Supreme Court are classic mechanisms of checks and balances whereby one branch restrains another. By contrast, a fixed presidential tenure and independent electoral mandate (through the Electoral College rather than Congress) reflect the separation of powers and executive independence rather than inter-branch checks and balances.