For a reversible reaction with a one-step mechanism, A B , the rate of the forward reaction is ratef = 3.2 x 10-6 s-1 [A] and the rate of the reverse reaction is rater = 4.6 x 10-4 s-1 [B]. What is the value of Kc for this reaction? A) 2.5 x 10-11 B) 7.0 x 109 C) 7.0 x 10-3 D) 1.5 x 10-9