A. 2 B. 3 C. 4 D. 5 Answer Pentane (C5H12) is an organic compound and an alkane with five carbon atoms. Pentane has three structural isomers. These are n-pentane, Iso-pentane and neo-pentane.Pentane means exclusively the n-pentane isomer; the other two being called isopentane (methylbutane) and neopentane (dimethylpropane). Cyclopentane is not an isomer of pentane. Structures of all the three isomers are given here.Option B is correct.