The contrast that best helps develop the theme of friendship in "Roll of Thunder, Hear My Cry" is the contrast between T.J.’s friendship with R.W. and Melvin and his friendship with Cassie and Stacey.
This contrast highlights T.J.'s complex relationships and the choices he makes regarding loyalty and friendship. His friendships with R.W. and Melvin reflect negative influences and betrayal, while his interactions with Cassie and Stacey represent sincerity and a deeper, more meaningful bond. This juxtaposition emphasizes the theme of friendship by illustrating the consequences of choosing friends wisely and the impact those choices can have on one's character and values.