The correct answer is:
B. It becomes a law.
Explanation:
After the House of Representatives and the Senate have both approved the bill, the bill is enrolled and sent to the President, the President has the power to sign and approve the bill so it becomes a law, or to return it with objections and observations to the House where it was originated, but if the President doesn't sign the bill and doesn't return it after 10 days, the bill becomes law only if the Congress is still in session, if the Congress is no longer in session then it is called a pocket veto.