Which sentence is an example of indirect characterization? my younger sister was clearly frightened by the booming thunder and flashes of lightning. my friend often displays childish and immature behavior when he doesn’t get his way. i couldn’t believe how surprised and overjoyed my mother was when she received the news. i am quick to say you and return the favor if someone does something nice for me.

The correct option is this: I AM QUICK TO SAY THANK YOU AND RETURN THE FAVOR IF SOMEONE DOES SOMETHING NICE FOR ME.
In literature works, there are two basic types of characterization, they are direct and indirect characterization. Direct characterization occur when the author directly tell the readers about the characters of a particular person in the play. Indirect characterization occurs when the personality of a character in the play is revealed via the character's speech, action or appearance.
In the option D chosen as the right answer for this question, the character reveals that he is a grateful person through what he said about himself.