the refusal by an official, such as the president of the united states or a state governor, to sign a bill into law is known as a

Veto

Explanation: The president’s power to refuse to pass a bill into law is know as a veto. After a bill has been passed by congress, it is then forwarded to the President who may choose to refuse the bill or approve it within 10 days, inclusive of Saturdays but not Sundays. If the president refuses the bill, it can only be enacted into law if two-thirds of both the Senate and the House vote to reverse the President's decision.

the answer is a. or c.

the answer is b, encourage free trade