D. It agreed to invade Poland at the same time as Germany and split
Polish territory.
Explanation:
The U.S.S.R invaded in relatively close time to Germany, and Poland was split into two sectors, in which the Eastern half was given to the U.S.S.R as a buffer zone, while Germany took control of Western half of Poland. This was part of the Non-aggression pact, in which the U.S.S.R hoped to use the bought time to train and equip their armies.
