What was the Reagan Doctrine?

The Reagan administration’s policy to liberate South America from European imperialism.
The Reagan administration’s system for codifying other nations by the level of danger they posed to the United States.
The Reagan administration’s strategy to overwhelm the Soviet Union’s global influence.
The Reagan administration’s plan to rid Asia from Communism through indirect intervention.
Is it the last one?

There's a better answer.

https://2001-2009.state.gov/r/pa/ho/time/rd/17741.htm

Yes, you are correct. The Reagan Doctrine was the Reagan administration's plan to rid Asia from communism through indirect intervention. It was a foreign policy strategy that aimed to support and provide assistance to anti-communist groups around the world, particularly in countries where the Soviet Union and its allies were supporting communist movements. This strategy was implemented as a response to the perceived threat of Soviet expansionism during the Cold War. The Reagan Doctrine aimed to roll back Soviet influence and promote democracy and capitalism as alternatives to communism.