Answer:
B. Overriding a presidential veto; is the correct answer.
Step-by-step explanation:
The United States of America's constitution imposes that State's power should be divided in to three branches: the Executive Branch; the Judiciary Branch; and the Legistative Branch which is therefore materialized as the Congress, which includes the House of Representatives and the Senate.
Amongst the powers of the legislative branch - the Congress - there is the power to override a presidential veto. That is, to vote on a bill, even though it has already been vetoed by the chief of the Executive Branch - the President himself. In order to proceed on doing so, it is required a minimum of two-thirds vote - 66% of the Congress members - in each Chamber.