Question

which revolution first convinced U.S officials they had to stop the spread of communism in the Western Hemisphere?

A) the assassination  of Rafael Trujillo in the Dominican Republic 
B) the coup to overthrow Juan Bosch in the Dominican Republic 
C) Fidel Castro's revolution in Cuba
D) the revolution to overthrow Salvador Allende in Chile 

Answer 1

I believe the answer is: C. Fidel Castro's revolution in Cuba
Prior to this revolution, united states government believed that the communist principles from the soviert union was too extreme for the population in Western hemisphere.
Seeing how fidel castro able to won the cuban revolutionary with this principle make United states became aware of the communism threat in western hemisphere.

Answer 2

The answer is Fidel Castro's revolution in Cuba.

After this, the U.S realized that communism was taking over fast and they needed to do something about it.

(The other answer on here is better, but I just wanted to confirm that this answer is correct!) :D