Answer:
a. Vetoing laws passed by Congress.
Step-by-step explanation:
The veto power is the power to unilaterally stop an official action, especially if this refers to a piece of legislation. In the United States, all bills passed by both houses of Congress are to be presented to the President. If the President does not approve the bill, he may return this unsigned to the house of Congress in which it originated. The returning of the unsigned bill to Congress is considered a veto.