In "The Scholarship Jacket" by Marta Salinas, the event that helps develop Marta's character is her decision to stand up for what she believes in. When she learns that her principal is going to deny her the scholarship jacket she has earned because her family can't afford to pay for it, Marta refuses to accept this injustice. She confronts the principal, argues passionately for her right to receive the jacket, and even threatens to expose the unfairness of the system to the school board. This event shows Marta's determination, integrity, and willingness to fight for what is rightfully hers, which are all important aspects of her character development in the story.