Final answer:
In the 1990s, Mexico experienced a movement towards a more democratic political system, with increased political participation and the holding of fairer elections after decades of PRI dominance. The correct choice of action is B. a more democratic political system.
Step-by-step explanation:
An overall trend in Mexico in the 1990s was a movement toward a more democratic political system. This transition was part of a larger regional trend in Latin America, where many nations moved away from authoritarian regimes and towards democracy. While the PRI (Institutional Revolutionary Party) had dominated Mexican politics for decades, fostering a one-party state, there were strides made to widen political participation and hold fair elections.
This shift played into the broader context of the post-Cold War era where many countries transitioned from socialist policies to embrace democratic institutions and the economic policies associated with them.