# The correct acid strength order of the compounds

$\begin{array}{1 1}(a)\;(i )> (ii) > (iii)&(b)\;(iii) > (ii) > (i)\\(c)\;(ii) > (i) > (iii)&(d)\;(i) > (iii) > (ii)\end{array}$

Nearer the chlorine to the -COOH group,stronger the acidity((i) > (iii) > (ii))
Hence (d) is the correct answer.