What Is the Principal Reason That American Courts Must Depend

What is the principal reason that American courts must depend on legitimacy to ensure compliance with their decisions?

A) Courts usually lack independent mechanisms to enforce their decisions.
B) Most court decisions are unpopular.
C) The president and Congress are prohibited from enforcing judicial decisions under the separation of powers.
D) States may nullify illegitimate judicial decisions.
E) The Bill of Rights declares judicial legitimacy.