Identify the segment in the sentence which contains the grammatical error.
After the match, every player of the team went back to its house.

He became rich overnight. What part of speech is 'overnight'?

The nightingale is a singing bird. In this singing is a/an --

I Came home after the rain -----.

The Doctor took the round in the hospital. Here 'round' is a/an ---

Alumni is the plural from of