0.10 M hydrofluoric acid is titrated with 0.10 M of sodium hydroxide solution

the Ka of HF is 6.8 x 10^-4. Which indicator is the most appropriate for signaling the end point of the titration?

A. bromphenyl blue (pH 3-4.5)
B. phenolphthalein (pH 8-10)
C. Thymol blue (pH 1.5-2.5)
D. alizarin yellow R (pH 11-12)
E. bromthymol blue (pH = 6-7)

Thanks in advance.

When titrating a weak acid like HF with a strong base like NaOH, the pH at the equivalence point will be slightly (1 or 2 pH units) toward the alkaline side (i.e. between pH 8 and 9). You want an indicator that changes color in that same pH range, so phenolphthalein is the one.