What can a reader use to make an inference about character?
a. research into other books written by the same author
b. information the author has provided in the footnotes
c. clues from the characters actions, interactions and words
d. information about the character found in outside sources

The correct answer is option C.

In order to make inferences about a character, the reader resort to the "clues from the character's actions, interactions and words".

As the story unfolds, the reader takes information from the characters' actions in order to understand her or his feelings, thoughts, and ways to behaving.

For example, feelings such as love, passion, envy, jealousy, or competition, may lead a character to kill a person or to cheat on his wife, etc.  

to gain popularity at school, fitzgerald wrote plays for the school and cast himself as the star. he also joined one of the universitys most prestigious clubs.