4.) how another character reacts to the main character
Explanation:
Indirect characterization on literature and artistic plays are everything that isn´t explicitely said by the narrator, or shown in the character, indirect characterization´s examples are what the character says, or the thoughts by him, also how other character react to him or say about him, everything that is shown about him, or said about him by the other characters and how they react to his actions is indirect characterization.
By the mother coming to school and the some kids mock her hairstyle, it reinforces the what the narrator thinks while also hurting the mothers feelings making the situation worse