Which of the following best characterizes the source of the UN's strength in foreign policy?

a$.$ The UN has a vast and powerful standing army that can be deployed.

b$.$ The UN has considerable powers and is a well$-$organized body that can make quick, decisive decisions.

c$.$ The UN has both considerable monetary power and a large standing army that gives it authority throughout the world.

d$.$ The UN serves as a useful forum for international discussions and as an instrument for multilateral action.