Answer:
The answer is: what
Step-by-step explanation:
It's simple really, once you start writing a sentence you gradually begin to formulate a thought that needs to be built upon with the end goal being an effective paragraph or piece of information.
If you take "mexico" in this context you will need to include a what, in order to make a who. by "who" you could mean what, but in reality it's likely that mexico can be, in this case a "what"
So, the answer we arrive to is "what"
