C.The setting takes place in a modern time in familiar place.
Explanation:
Realistic fiction refers to a form of narrative that elaborates upon events, ideas, and characters that are set in a time and place that, to a greater or lesser degree, ought to be familiar to the reader. In today´s world, we are commonly said to be living in modernity, and though it is difficult to define and pinpoint the beginning of modernity, one could avoid the difficulties by stating that modernity is the time span where various cultural groups share the same political, economic, and humanist values that stem from the Illustration in the 18th century and that are still relevant to this day, which is what would make the setting familiar to us, today. As for the place being familiar, that merely implies that it would be something easily recognizable and identifiable by the reader in today´s context.
I think that 20% of smokers wanting to quit smoking would be too narrow because that is only 20 people out of 1,000,000 that want to quit smoking versus 90% of people that would lie to quit.