The incorrect statement regarding chirality is :
(A)A racemic mixture shows zero optical rotation.
(B) `` S _{ N } 1 `` reaction yields `` 1: 1 `` mixture of both enantiomers.
(C)The product obtained by `` S _{ N}2 `` reaction of haloalkane having chirality at the reactive site shows inversion of configuration.

(D)Enantiomers are superimposable mirror images on each other.