A 5000-ML Solution of 0 $\times$ 10^-5)is Titrated with a 0 $\times$

Multiple Choice

A 50.00-mL solution of 0.0797 M ammonia (K_b = 1.8 $\times$ 10^-5) is titrated with a 0.0315 M solution of hydrochloric acid as the titrant.What is the pH of the base solution after 23.88 mL of titrant have been added? (K_w = 1.00 $\times$ 10^-14)

A) 11.08
B) 9.88
C) 4.12
D) 4.74
E) 12.90