Who is they?
Professors do a lot for students, but they are rarely thankful.

OPTIONS:
- Professors
- students

A:
students

Who is they?
The zookeepers make sure to feed the chimps on a daily schedule because they are required to do so under animal cruelty regulations.

OPTIONS:
- The zookeepers
- the chimps

A:
The zookeepers

Who is it?
The cat broke the glass because it was clumsy.

OPTIONS:
- The cat
- the glass

A:
The cat