Which of the following institutions completes the excerpt below?
instead of trying to reduce the burden of taxation, the republican senate has spent its full time trying to defeat the plan for a which if organized will cut down and limit military armament among all the great powers, and will make war [almost] if not impossible. if the senate destroys the then the united states must begin at once to arm on a greater scale than any other nation in the world.3
—former u. s. treasury secretary william g. mcadoo, 1920
a. league of nations
b. union of soviet socialist republics
c. mandate system
d. bolshevik revolution