The reaction of propene with HOCl proceeds via the addition of

Question

$\begin{array}{1 1}(a)\;H^+\text{ in the first step}\\(b)\; Cl^+\text{ in the first step}\\(c)\;OH^-\text{ in the first step}\\(d)\;Cl^+\;and\;OH^-\text{ in a single step}\end{array}$