The reaction Br2 + CH3Br → CH2Br2 + HBr was carried out. Which of the following mechanism steps is productive, but relatively unlikely to occur? A) Br· + CH3Br → HBr + ·CH2Br B) Br· + ·CH2Br → CH2Br2 C) Br· + Br2 → Br2 + Br· D) Br· + ·CH3 → CH3Br