IN: Which person is they?
The Apes were determined to be contaminated by disease specialists, so they were forced to be released in secured captivity.
OUT: The Apes

IN: Which person is he?
The farmer proudly revealed his favorite chicken, because he laid a golden egg.
OUT: his favorite chicken

IN: Which person is him?
The Secretary and the President met about him being elected.
OUT: the President

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