Correct Answer - A
In R-s configuration , priority sequence is decided by the atoms directly attached to the chiral carbon are arranged in decreasing atomic number.
From the given groups, sulphur (S) has the highest atomic number i.e, 16 therefore , its gets highest priority.
The priority order is
`I, Br, Cl, -SO_(3)H,SH,F,-O-overset(O)overset(||)(C )-R, OR, OH, NO_(2), NR_(2), NHCOR, NHR,NH_(2),CO_(2)R, CO_(2)H,CONH_(2),COR,CH_(2)OH,CN,CH_(3),C_(6)H_(5),CHR_(2),CH_(2)R,CH_(3),D,H`.
