The United States sponsored the contras in Nicaragua because they hoped they would

a curb terrorism
b promote human rights
c limit drug trafficking into the U. S.
d defeat the Sandinistas

D

Explanation:  

Contra or against, shortening of counterrevolutionaries, also self-styled as the Nicaraguan Resistance, is the name given to the groups of insurgents financed by the United States that tried to put an end to the revolutionary government (1979-1990) of the Sandinista National Liberation Front (FSLN), which ruled Nicaragua after the overthrow of the dictatorship of Anastasio Somoza and his family in July 1979.

d

Explanation:

Contra or against, shortening of counterrevolutionaries, also self-styled as the Nicaraguan Resistance, is the name given to the groups of insurgents financed by the United States that tried to put an end to the revolutionary government (1979-1990) of the Sandinista National Liberation Front (FSLN), which ruled Nicaragua after the overthrow of the dictatorship of Anastasio Somoza and his family in July 1979.

its many islands, high mountains, and remote peninsulas isolated population centers.