The correct answer is - b. Corruption and high crime rates are a serious challenge.
Both Brazil and Mexico are countries that have huge problems with the corruption and the high crime rates.
The corruption seems to be an integral part of their respective societies and it can literary be found everywhere and about everything, from the most ordinary things on the streets, to the highest circles of the government and the institutions.
The high crime rates are also kind of a trademark for both of these countries. The cartels have huge power and influence in these countries, and it seems that doesn't matter how much the government tries to destroy them it doesn't really have any effect. In Mexico, the situation is so bad that there are multiple areas that are totally controlled by the cartels, where they have their own rules and the government doesn't have any authority at all.