Which pronoun has an unclear antecedent in the following sentences?

The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made them happy.

Their
It
Them
No unclear antecedents

Question

Which pronoun has an unclear antecedent in the following sentences?

The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made them happy.

Their
 It
 Them
 No unclear antecedents

AZ · Answer

@lely any ideas?

Is there a word that is vague in who it is referring to

lely · Answer

a is the answer

AZ · Answer

That's not right

So read the sentence

6th grade students liked volunteering THEIR time

who does the word `their` refer to?

AZ · Answer

The sixth-grade students liked volunteering their time to read to the elderly people in the hospital. It made them happy.

what about the word `them`

who does `them` refer to?