At the Yalta Conference, what was Stalin promised in exchange for the Soviet Union entering the war ...

At the Yalta Conference, what was Stalin promised in exchange for the Soviet Union entering the war against Japan?
 
  a. Significant influence over China as long as he did not intervene in Hong Kong.
  b. Preeminent interests in Manchuria as long as he agreed not to assist Communist China.
 c. A division of the interests in the breakup of the Japanese Empire.
 d. Sakhalin Island north of Japan, on the Kamchatka peninsula
 e. Re-extension of Soviet placement in Port Arthur on the Korean peninsula with a promise to remain out of the Chinese Civil War.