I want to know the answer to the following question:
Along with the Mongolian People's Republic and the People's Republic of China, what country did the RSFSR border to its southeast?
All the background I'm provided with is that "The international borders of the RSFSR touched Poland on the west; Norway and Finland on the northwest; and to its southeast were the Democratic People's Republic of Korea, Mongolian People's Republic, and the People's Republic of China.". Is that enough to answer the question?