Which best explains how the Institutional Revolutionary Party (PRI) maintained power in Mexico for many years?

It defeated opposition parties by controlling congress and using election fraud.

It ruled so well that people prospered and opposing parties did not succeed.

It acted like a dictatorship and jailed those who opposed the way they ruled.

It offered the working class many benefits and kept dissension to a minimum.

"It defeated opposition parties by controlling congress and using election fraud" and "It acted like a dictatorship and jailed those who opposed the way they ruled" could be right answers. PRI government was never recognized as a dictatorship because they maintained a very small and controlled democracy, and there were still elections. However this elections where most of the time manipulated and fraudulent. So "it defeated opposition parties by controlling congress and using election fraud" explains the reason why the PRI maintained power in México for many years. So that's the right answer.

I believe the answer is: It defeated opposition parties by controlling congress and using election fraud.

The Institutional Revolutionary Party was known to advocating an increase in government control toward any resources and porperty which exist in Mexico. The party managed to hold uninterrupted power for more than 70 years by rigging election and controlling the legislative process in Congressional seat.