Determine the pH for the following solutions:

a. [H3O+]=2.0×10−8M
Express your answer using two decimal places.

b. [H3O+]=8.3×10−2M
Express your answer using two decimal places.

c. [OH−]=7.5×10−4M
Express your answer using two decimal places.

d. [OH−]=0.002M
Express your answer using one decimal place.