A 2000 ML Solution of 0 $\times$ 10^-5

A 200.0 mL solution of 0.40 M ammonium chloride was titrated with 0.80M sodium hydroxide.What was the pH of the solution after 50.0 mL of the NaOH solution were added? The K_b of ammonia is 1.76 $\times$ 10^-5.

A) 9.25
B) 4.75
C) 11.22
D) 5.02
E) 8.98