How Many Moles of HCl Must Be Added to 1

Multiple Choice

How many moles of HCl must be added to 1.0 L of 1.0 M NH₃(aq) to make a buffer with a pH of 9.00? (pK_a of NH₄⁺ = 9.25)

A) 0.36 mol
B) 0.44 mol
C) 0.56 mol
D) 0.64 mol
E) 1.8 mol