The rate of a chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of B is increased by 100%, which of the following is closest to the percent change in concentration of chemical A required to keep the reaction rate unchanged?

A) 100 % decrease
B) 50% decrease
C) 40 % decrease
D) 40 % increase
E) 50 % increase

The OA is D. How?