How did the Reagan Doctrine affect the Cold War?

It provided intricate defense programs to block Soviet attempts to start a nuclear war.
It reinforced the ideas of the Monroe Doctrine by removing Soviet influence in the Western Hemisphere.
It established a policy for dealing with the imperialistic nature of another superpower.
It provided assistance to resistance movements in Communist-backed governments.

i think it is A & D?

Wait I think one is B. So A & B?

You were right the first time -- A and D.

Yes, you are correct. The Reagan Doctrine indeed had both of the effects you mentioned:

A) It provided intricate defense programs to block Soviet attempts to start a nuclear war. This refers to the Strategic Defense Initiative (SDI), also known as "Star Wars," which was a plan to develop space-based missile defense systems. The aim was to render Soviet offensive capabilities useless and deter them from starting a nuclear war.

D) It provided assistance to resistance movements in Communist-backed governments. This aspect of the Reagan Doctrine involved supporting anti-communist rebel groups, often known as "freedom fighters" or "Contras," in countries such as Afghanistan, Angola, Nicaragua, and Cambodia. By doing so, the United States aimed to undermine Soviet-supported governments and insurgencies around the world.

It's worth mentioning that the other options you provided, B and C, are not directly associated with the Reagan Doctrine. However, they are indeed aspects of U.S. foreign policy during the Cold War but may not be specifically tied to the Reagan Doctrine itself.