If a state increases the state sales tax rate from 7% to 10%, this rate increase leads to an increase in tax revenues. Based upon what the Laffer curve tells us, which of the following statements is most correct:

A. The optimal sales tax rate is greater than 10%

B. This state would be on the upward sloping side of the Laffer curve

C. The optimal tax rate is lower than 10%

D. Not enough info