A 10-Liter Solution Contains 0 $\times$ 10^-4)

Multiple Choice

A 1.0-liter solution contains 0.25 M HF and 0.41 M NaF (K_a for HF is 7.2 $\times$ 10^-4) .What is the pH of this solution?

A) 3.14
B) 3.36
C) 2.93
D) 0.21
E) 10.64