How fast a reactant is used up to how fast a product is formed is

a.)the equilibrium
b.)the rate of reaction
c.)solution concentration
d.)the catalyst

Option (B) is the correct answer.

Explanation:

The rate of a reaction is defined as how rapidly the reactants convert into products.

There are various factors which can help in increasing the rate of a reaction like addition of a catalyst, temperature, change in concentration etc.

Thus, we can conclude that out of the given options how fast a reactant is used up to how fast a product is formed is the rate of reaction.