Answer choice would be D, answer choice B, is the boxes net force. Velocity = distance/time. The correct answer is D. I hope this helps!
The differential rate expression for the rate of change in the concentration of B with time is
-rB = dCB/dt = kCB^n
where k is the rate constant and
n is the order of the reaction
This is assuming that the rate is only affected by the concentration of B and the order of the reaction is in the nth order.
