Which Two Events Account for a Majority of Immigration Activity

Which two events account for a majority of immigration activity in relation to U.S. Latinas/os of Cuban Heritage?

A) Fidel Castro's rise to power in 1959 and the Cuban Missile Crisis.
B) The fall of the USSR and the 1980 Mariel Boatlift.
C) The 1980 Mariel Boatlift and the Cuban Missile Crisis.
D) Fidel Castro's rise to power in 1959 and the 1980 Mariel Boatlift.