Which of the following is the correct order of decreasing ionic size is

Question

$\begin{array}{1 1}(a)\;K^+ > Ca^{2+} > S^{2-} > Cl^-\\(b)\;S^{2-} > Cl^- > K ^+ > Ca^{2+}\\(c)\;K^+ > Cl^- > Ca^{2+} > S^{2-}\\(d)\;Cl^- > K^+ > S^{2-} > Ca^{2+} \end{array}$