IN: Which person is he?
King Leonidas was more respected then King Henry because he unfairly taxed the people.
OUT: King Henry

IN: Which person is they?
The students fell asleep during the professor's lectures because they were boring.
OUT: the professor's lectures

IN: Which person is they?
The police captured the criminals because they were more prepared.
OUT: The police

IN: Which person is he?
Dan modified Harry's car because he asked politely.
OUT:
Harry