Answer: Option (a) is the correct answer.
Step-by-step explanation:
Rate of reaction is defined as the rate at which a chemical reaction occurs. That is, it tells how rapidly or slowly the products are formed.
Mathematically, Rate =
![(-\Delta [reactants])/(\Delta t)](https://img.qammunity.org/2019/formulas/chemistry/college/alx9inh33od5c41emilskbs4mcu3c3wmtp.png)
It also tells the number of successful collisions taking place.
Thus, we can conclude that the speed at which products form is measured by the reaction rate.