The correct option is D (a) and (b) above
The iodoform reaction been used as a chemical test for the presence of a methyl ketone moiety.
Acetone and acetaldehyde have methyl ketone(−COCH3) moiety thus give iodoform reaction.
Benzaldehyde gives Tollen's test but acetophenone does not. On the other hand, acetophenone (Ph−COCH3) gives iodoform test because it has methyl ketone moeity (−COCH3) but benzaldehyde does not because it doesnot have methyl ketone moeity (−COCH3). thus correct option is (d).