# Complete the following reaction by filling in the necessary reagents.

$\begin{array}{1 1}(a)\;(1)NaCN,(2)PhMgBr,(3)H_3O^\oplus\\(b)\;(1)AlCl_3\;and\;Benzene,(2)PhMgBr,(3)H_3O^\oplus\\(c)\;(1)Mgmetal,(2)Benzene,(3)H_3O^\oplus\\(d)\;\text{Above all}\end{array}$

Hence (a) is the correct answer.