The PH of a 0

The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0 °C is 4.48. What is the value of K_a for HBrO?

A) 3.3 × 10^{- 5}
B) 6.0 × 10^{- 5}
C) 1.1 × 10^{- 9}
D) 3.0 × 10⁴
E) 2.0 × 10^{- 9}