Question

the role of the senate in regard to treaties is to
approve international treaties.
advise during negotiations.
have the president of the senate sign the treaty.
negotiate the terms and conditions of the treaty.

Explanation:

In the United States, the Constitution gives the Senate the power to approve international treaties with a two - thirds majority vote. The Senate does not negotiate treaties (that's mainly the executive branch's role), nor does the Senate president sign treaties, and while there may be some informal advice, the main role is approval.

Answer:

approve international treaties.