The correct answer is C. In realistic contemporary drama you would most likely find a situation that is unremarkable. "Realistic" is often interpreted as ordinary; in contrast with fantasy, which deals with the impossible (or at least the scarcely possible), Realism describes common situations. Its goal is to describe human lives and society in a more "truthful" (or even quasi-documentary) manner. Stendhal's metaphor for the novel (a mirror which someone carries along a road, and which reflects both the sky and the mud) is pertinent here.
The option that you would most likely find in realistic contemporary drama is a situation that is unremarkable. In today's plays, often there are some events and situations that aren't special in any way, but rather represent everyday events that may happen to anyone. The other options can often be found in Shakespeare's or some older plays, but rarely in contemporary dramas.