What is the best caption for this political cartoon?

a) The Soviet Union, led by Brezhnev, is protecting the brief flame of political freedom found in Czechoslovakia.

b) The Soviet Union, led by Brezhnev, investigates the Prague Spring reforms.

c) The Soviet Union hides from neighboring countries the flame of political freedom found in Czechoslovakia.

d) Soviet leader Brezhnev douses the spirit of freedom born during the Czech Prague Spring.