QUES:
Who is they in the following sentence?

The NSA sent their agents in the field to retrieve intelligence because they need people in the field to do the field work.

ANS:
The NSA

QUES:
Who is she in the following sentence?

The grandmother threw her granddaughter to her death because she felt jealous.

ANS:
The grandmother

QUES:
Who is she in the following sentence?

The manager fired the intern because she was too rebellious.

ANS:
the intern