Why do authors use allusions in fiction and literary nonfiction texts?

A.
to call attention to certain words by creating rhythm with their words
B.
to create a contrast between how things seem and how they really are
C.
to help readers make connections by referencing an event, a person, or another text
D.
to make readers pause and think about the contradiction that has been created

through negative experiences we learn many things its sort of like karma if u do something bad to someone and u get a consequence u dont like the next time u wont do it again and as for positive ur not really learning anything and another example for negativity people didnt want barrack obama as president because they thought he was the worst and he was taking but now we have donald trump   and hes   is not anyone and shut down the government over sum petty stuff unlike barrack obama who shut down the government because they did not want to give health care to the community and now these people who want him out want him in now

i think it's either 'to expose the corruption of the communists in russia', or 'to criticize animal brutality by communists in russia.'  

hope this ! : )

ok so it would be d because that would catch attention and make them what to read it.