Please help me fill this exercise I'm a bit confused I just need some kind of verification

Humans have survived and thrived in mexico city by using technology to create greater access to land. when the spanish conquered the aztec capital, tenochtitlan, in the 16th century, they built mexico city by draining the lakes and filling in the lake water to create more arable land for agriculture. this technique of land reclamation has continued to be fundamental to human civilization in mexico city. 

Ithink the best answer is d increased stability of all other biomes

Answer (b) they're often rural migrants with no title to housing or rights to established businesses