What can Mexico City do to stop the sinking?

González urges action to address the issues, such as finding alternative sources of drinking water, artificial aquifer recharge and renovating the water infrastructure, some of which are more than 100 years old. The measures may cost up to US $1 billion per year, for the coming 15 years.

Explanation:

i believe your answer is d)

islam spread slowly through much of africa through trade and preaching.