QUES:
Who is he in the following sentence?

Steve Ballmer took over as CEO of Microsoft after Bill Gates because he was a unicorn.

ANS:
Steve Ballmer

QUES:
Who is they in the following sentence?

The army organized their forces to sneak past the Decepticons in the city because they needed to use stealth to their advantage.

ANS:
The army

QUES:
Who is he in the following sentence?

Jack the ripper killed John, but he was not caught yet.

ANS:
Jack