HClO<HClO2<HClO3<HClO4
HClO4<HClO3<HClO2<HClO
HClO4<HClO<HClO2<HClO3
HClO2<HClO3<HClO4<HClO
Correct order of acid strength is:HClO+1<HClO2+3<HClO3+5<HClO4+7(∝acid strength∝oxidation number)Hence, option A is correct.