Compound(s) among the following with an asterisk (*) asymmetric carbon is/are:

1.  (a), (b), (c), (d)
2.  (a), (b), (c)
3.  (b), (c), (d)
4.  (a), (c), (d)

Asymmetric carbon maeans any saturated sp3 carbon having four diffrent goups or atoms. In compound (iv), carbon Fulfills its two of its valencies with

two hydrogen atoms as similar atoms hence not asymmetric.While other three substates are asymmetric where all 4 groups or atoms are diffrent.