If the president of the United States disagrees with a law passed by Congress, he or she can this law.
A. veto
b. adopt
c. ratify
d. sign

Veto

Explanation:

The veto is a part of the checks and balances system in the  Government, which prevents one branch from gaining too much power.

If the President thinks an act or bill that Congress has passed is unconstitutional or unfair, they can veto it, which will prevent it from becoming a law. This action "checks" Congress/ The Legislative Branch.

The Legislative Branch can then "check" the Executive Branch of the President and they can override the veto, if they get enough votes in Congress. This will allow the bill to pass.  If they can't get enough votes, the bill won't be able to pass.

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