The correct answer is 3 i.e. Only 1, 2 & 4 are correct. Explanation: The organic compounds have two names: common name and official names (IUPAC names). The official names or systematic names of organic compounds were given by the International Union of Pure and Applied Chemistry in 1958, so they are called IUPAC names or IUPAC nomenclature. To name hydrocarbons by the IUPAC method, we should remember the following points : The number of carbon atoms in a hydrocarbon is indicated by using the following stems: One carbon atom Meth Two carbon atom Eth Three carbon atom Prop Four carbon atom But Five carbon atom Pent Six carbon atom Hex Seven carbon atom Hept Eight carbon atom Oct Nine carbon atom Non Ten carbon atom Dec A saturated hydrocarbon containing a single bond is indicated by writing the word 'ane' after the stem. An unsaturated hydrocarbon containing a double bond is indicated by writing the word 'ene' after the stem. An unsaturated hydrocarbon containing a triple bond is indicated by writing the word 'yne' after the stem.