For an elementary reaction, A + 2 B → 3 C + D which of the following rate expressions is valid for the reaction rate?
A. k[A][B] - k[A][B] + k[A][B].
B. 2 + k[A]2[B] + 2k[A][B] + k[C].
C. 3[D] - k[C]3[D] + 3k[C][D].