The only character who believed in doodle throughout the story of “the scarlet ibis” was a. daddy b. mama c. aunt nicey d. the narrator

I believe it is D. The Narrator.

since it is asking for her reaction to elnora's trouble at school you can rule out any answers with a positive response (b). then you can rule out (d), this is because it does not show the mother's reaction but the daughter's response. that leaves you with two options (a) and (c), by looking at the options you can rule out (c) because it isn't referring back to elnora's issues at school.