Given below are two statements, one labelled as Assertion A and the other labelled as Reason R.Assertion A: The Bolsheviks shifted their focus from world revolution to building socialism within the Soviet Union.Reason R: The Soviet defeat in war with Poland in 1921 and failure of revolution in Europe shifted the focus of Soviet foreign policy.Codes:

• A. Both A and R are true, but R is not the correct explanation of A.
• B. Both A and R are true and R is the correct explanation of A.
• C. A is true, but R is false.
• D. A is false, but R is true.