Answer: The president vetoes or refuses to sign a law that he does not agree with.
Step-by-step explanation:
Checks and balances refers to a system whereby a branch of a government can make amendment or veto the acts of other branch in order to curtail one branch from having too much power.
In this case, the president who is a member of the executive branch can vetoes or refuses to sign a law that he does not agree with. Therefore, the correct option is C.