When a carbon atom is linked to four different groups it is said to be chiral carbon atom. when alpha hydrogen atom of an alkane is replaced by a functional group we get corresponding compound. IUPAC name for lowest molecular mas optically active alkene is

Question

$ (a)\;3-methylex -1-ene \\ (b) \; 3-methylpt-2-ene \\ (c) \; 3-methylpent-1-ene \\ (d)\;1-methylpent-3-ene $