What are possible reasons for the decline of the mayan empire

Mysterious Decline of the Maya. From the late eighth through the end of the ninth century, something unknown happened to shake the Maya civilization to its foundations. One by one, the Classic cities in the southern lowlands were abandoned, and by A.D. 900, Maya civilization in that region had collapsed.

Hope this helps. :P

this is too much for 25 pts. and brainliest

i would think its c but i'm not sure