d
(d) \(C{H_3} - C{H_2} - \mathop {\mathop {{C^*}{\mkern 1mu} {\mkern 1mu} {\mkern 1mu}  - {\mkern 1mu} }\limits_{|{\kern 1pt} \,\,\,\,\,\,\,\,{\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} }^{|\,\,\,\,\,\,{\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} } }\limits_{H\,\,\,\,\,\,\,\,{\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} }^{N{H_{2\,\,\,\,\,\,\,}}} C{H_3}\)

Chiral centre is present. Hence, it exists as optical isomers or enantiomorphs.