Which of the carbon atoms present in the molecule given below are asymmetric?

Chiral molecules contain one carbon atom surrounded by four nonidentical species. All straight chain molecules cannot be chiral because of the presence of two or more identical groups like hydrogens. Even the carbons with double or triple bonds to a group cannot be considered as a chiral carbon. An asymmetric carbon needs to be surrounded by four species different from each other through covalent bonds. Hence, the atoms b and c are asymmetric. Option (ii) is the correct answer.