IN: Which person is they?
The NSA sent their agents in the field to retrieve intelligence because they need people in the field to do the field work.
OUT: The NSA

IN: Which person is he?
Mike helped Jack with his assignment because he felt like doing so.
OUT: Mike

IN: Which person is they?
The academic clubs lost their members because they were poorly funded.
OUT: The academic clubs

IN: Which person is he?
Kevin stared at Michael and he got his attention.
OUT:
Kevin