Why does Holden decide to write straddlers composition about allies basketball mitt?

Holden decides to write his composition about Allie's Baseball mitt because it holds deep personal significance for him. The mitt symbolizes his love and admiration for his deceased brother, Allie, and serves as a tangible reminder of their bond. By focusing on the mitt, Holden expresses his grief and nostalgia, showcasing his struggle to cope with loss and his longing for the innocence of childhood. The composition becomes a way for him to process his emotions and keep Allie's memory alive.