A 30.00 mL solution of 0.100M benzoic acid, a monoprotic acid, is titrated with 0.100M NaOH. The Ka is 6.3x10^-5. Determine the pH of the solution after the volumes of NaOH given were added. 
a. 0ml  b. 10.00ml c. 30.00ml d. 40.00ml