Final answer:
Leroy suggests that Rhoda's attempt to clean the stick was silly because blood cannot be washed off.
Step-by-step explanation:
In the dialogue, Leroy suggests that Rhoda's attempt to clean the stick was silly. According to Leroy, Rhoda thought she could wash off blood, but Leroy states that it can't be washed off. This implies that Rhoda's attempt to clean the stick was futile and she was mistaken in thinking that it could hide the evidence.