Question

Which of these is the strongest example of multilateral foreign policy?

One nation states publicly that it will refuse to trade with any nation that criticizes its leader.
One nation refuses to trade with a rival nation because it does not allow women to vote in an upcoming election.
Two rival nations go to war with one another over disputed territory.
Two allied nations enforce economic sanctions on a country until its government changes a key policy.

Answer 1

"Two allied nations enforce economic sanctions on a country until its government changes a key policy."

Reason: multilateral foreign policy involves two or more states cooperating on a common diplomatic or policy action. The sanctions by allied countries are a coordinated, joint effort, unlike the unilateral trade refusals or a bilateral war.