All of the following are reasons for Communist Russia's animosity toward the United States and the western powers except one. Which is the exception?

Question

a. Russia was not allowed to participate at the Treaty of Versailles.
b. Russia felt the U.S. delayed the 2nd front in WWII, resulting in additional Russian deaths
c. The U.S. delayed recognition of Communist government, after its takeover during WWI
d. The United States attempted to occupy the nations of Eastern Europe following Germany's defeat in WWII.

Is it A.

Answer 1

I disagree.
http://en.wikipedia.org/wiki/Treaty_of_Versailles