<span>C.All must do the best they can with the time they are given in life</span>
I guess formal and informal refer to two types of essay - you can write a formal essay where you avoid conversational language and such and where you need to be very professional, or you can write informally where you don't have to think about such things, it is very casual.
A. The use of youth-produced slang became more common.
C
Realist literature focuses on being in tune with the aspects of reality and daily life.
