Question

Complete the following sentence with the correct present-tense form of poder below.

Answer 1

So, "Ellos" means "they"
Podemos- we can
Pudieron- could
Pueden- may
Pudo- could
If you think about it it's not "Podemos" or "Pudo"
But, i could be wrong. "Podemos" does not make any sense.
So, that means is "Pueden".
Ellos Pueden. (they may)
Your answer is PUEDEN! 
:) i hoped this helped