" Which of the following is strongest conjugate base "

Which of the following is the strongest conjugate base ?

Strongest conjugate base is

Strongest conjugate base is

Strongest conjugate base is

Oxygen is more electronegative than chloride. In the series of oxyacids HOCI, HCIO_(2) , HCIO_(3) and HCIO_(4) , an increasing number of oxygen atom is bonded to the chlorine atom. Chlorine forms a number of oxyacids which differ in their stability order. Which of the following is the strongest conjugate base ?