The correct answer to this open question is the following.
Although you forgot to include the options to this question, we can say the following.
In order to protect US interests, the Carter Doctrine declared that the United States would use military force, particularly in the Persian Gulf.
On January 23, 1980, during his State of the Union address, US President Jimmy Carter had to declare that the United States was going to use its armed forces to defend its political and economic interests in the Middle East, especially, in the Persian Gulf. The Soviet Union had invaded Afghanistan in 1979, so the US President wanted to send a clear message to the Soviets in those Cold War years, that the United States did not fear to use the strength of the military to defend their interests in the Middle East region.
