Calculate the pH and the pOH of a solution containing a H₃O⁺ concentration = 2.5 × 10⁻² M.
a) pH = 1.60, pOH = 12.40
b) pH = 11.60, pOH = 1.40
c) pH = 2.40, pOH = 11.60
d) pH = 12.40, pOH = 1.60