Complete the following reaction:

Explanation

It is an example of Michael addition reaction. The carbonion formed by the base is (A). It adds to `(C=C)` to give intermediate carbanion (I), which is stabilised by the adjacent carbanion (I), which is stabilised by the adjacent (CN) group. (I) undergoes an E2 reaction to give (C ) and stabilised carbonion (II) `[overset(Θ)(CH)(CN)_(2)]`. II on reaction with `H_(2)O` gives product (D) `[CH_(2)(CN)_(2)]`.