b
(b) $C{H_3} - \mathop {\mathop {\mathop {CH}\limits_{|\,\,\,\,\,} }\limits_{C{H_3}} }\limits^{\,\,\, + \,\,\,\,\,\,} \, > \,\,C{H_3} - \mathop {\mathop {CH}\limits_{|\,\,\,\,\,}^{\,\,\, + \,\,\,\,} \,\,\,\,}\limits_{OC{H_3}} > \,\,C{H_3} - \mathop {\mathop {\mathop {CH}\limits^{\,\, + \,\,\,\,} \,\,\,\,\,\,\,\,}\limits_{|\,\,\,\,\,\,\,\,\,\,\,\,} }\limits_{COC{H_3}} $