The correct order of reactivities of nucleophilic addition across -C=O of the RCOR ,RCHO and ArCHO is

Question

$\begin{array}{1 1}(a)\;RCHO < ArCHO < RCOR\\(b)\;ArCHO < RCOR < RCHO\\(c)\;ArCHO < RCHO < RCOR\\(d)\;RCHO < RCOR < ArCHO \end{array}$