Answer:
Correct answer is by sending Soviet troops to Afghanistan.
Explanation:
Brezhnev doctrine was focused on the reaction of Soviet troops in the areas where the Socialism was endangered.
That is why the last option is correct as Soviets reacted with military assistance in Afghanistan.
All other options are not correct as they are showing the readiness of Soviet Union to lower the tension in certain period of crisis.
Russia last czar of Russia was czar nicholas II. he was overthrown is 1917 in what is called the Russian revolution.
The last statement. you have to limit power otherwise people would become evil
