The central character who is the focus of interest in a story is the a) motif b) antagonist c) central conflict d) protagonist

The protagonist because that is the main character in the story. in some stories there are many protagonists.

(D) Protagonist

Wrong - A: motif is a symbol or technique
Wrong - B: Antagonist presents opposition to the main character. ("Anti" Protagonist = Antagonist)
Wrong - C: Central conflict is the conflict/relationship between the protagonist and antagonist. 

It’s a hope that ; )