Following mechanism has been proposed for a reaction: $2\text{A} + \text{B} \rightarrow \text{D} + \text{E}$

Step I: $\text{A} + \text{B} \rightarrow \text{C} + \text{D}$ (slow)

Step II: $\text{A} + \text{C} \rightarrow \text{E}$ (fast)

The rate law expression for the reaction is