What Does the Persistent Congressional Obstruction Faced by President Obama

What does the persistent congressional obstruction faced by President Obama demonstrate?

A) Unitary leadership in the executive branch can overcome legislative opposition on policy matters.
B) Partisanship can increase the power of the president by increasing public support for the institutional presidency.
C) Unified government increases the possibility of the legislature closing the policy process to the president.
D) Divided government contributes to the ability of the legislature to constrain presidential power.