Question

what happened when the czechs tried to implement liberal reforms in 1968?
the communist government was forced to step down.
slovakia protested and blocked the proposed changes.
the ussr and other warsaw pact nations invaded.
czechoslovakian residents gained new civil liberties.

Explanation:

In 1968, the Prague Spring (liberal reforms in Czechoslovakia) was met with invasion by the USSR and other Warsaw Pact nations to stop the reforms. The communist government didn't step down, Slovakia didn't block (they were part of Czechoslovakia), and the reforms were suppressed so civil liberties weren't gained.

Answer:

C. The USSR and other Warsaw pact nations invaded.