Final answer:
Two-Bit's retort, "Who you calling bums?" demonstrates his defensive, prideful, and protective nature, indicating he values respect and loyalty within his peer group.
Step-by-step explanation:
When Two-Bit says, "Who you calling bums?" it suggests that he possesses a defensive character trait. He is quick to stand up for himself and his friends, indicating a sense of pride and a protective nature. His reaction also shows he does not tolerate being disrespected or labeled in an offensive way. Such a response could be prompted by his concern over his and his group's reputation or could stem from a deeper sense of loyalty and solidarity among his peers.