In the nitration of bromobenzene, a mixture of nitric acid and sulfuric acid are added to the bromobenzene and stirred at room temperature. Why is it important to keep the reaction mixture at room temperature rather than heating it?

a. To prevent bromobenzene from evaporating out of solution.

b. To prevent bromobenzene from precipitating out of solution.

c. To prevent di-substituted products from forming.

d. To prevent meta-substituted products from forming.

e. To prevent meta-substituted and di-substituted products from forming.