A. affect
Affect can sometimes be a noun, but it is mostly used as a verb that describes some sort of change or difference.
On the other hand, the word effect is not an action nor verb; it is a noun that refers to the result of a cause.
Answer
B or A but im leaning towards B
There is an archaic term "Exeunt" used to describe a situation where many characters leave the stage. "Exeunt Omnes" would be the stage direction for everyone to leave.