The correct answer is "C".
One of the main issues regarding foreign affairs between the United States and Mexico is the entrance of Illegal drugs to the United States by the US-Mexico Border.
After an agreement between the 2 governments, a joint team between US and Mexican Law enforcement agencies has been set up in the city of Chicago. This office set up operations in the last quarter of the year 2018.
Other efforts by the US government include the Merida Initiative, which includes a US$ 2.9 Billion aid by US Agencies to the Government of Mexico in order to fight organized crime and drug trafficking.