Ans: A)
HBrO and HBrO₃ are oxyacids where the acidic strength increases with the increase in the number of atoms attached to the central atom.
In both acids, oxygen is the most electronegative atom. In HBrO, the B atom is linked to only one O atom. In contrast, there are 3 electronegative O atoms surrounding the central B atom in HBrO₃ which would make the OH bond more polar and easily accessible. Thus, HBrO₃ tends to lose a proton readily than HBrO making the former more acidic.