b-cause that the right answer
the US was very concerned because of the fact that Cuba had nuclear missiles within range of Washington D.C. and the leader of Cuba was being heavily supported by the Russians which at this time the US were involved in a cold war with where each side was moments from launching nuclear missiles at one another.
The Qing Dynasty ruling from 1644 to 1912.
End of the first century or the beginning of the second century
