Either of the solutions you (A) have proposed (B) are acceptable to the union, (C) whose members (D) are willing to compromise.

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