The correct answer is D. 1, 2 and 3.
Statement 1 is correct. The gas supplied in cylinders for cooking is a mixture of propane (C3H8) and butane (C4H10). Propane and butane are both alkanes, which are hydrocarbons that are saturated with hydrogen.
Statement 2 is also correct. The thermal decomposition of alkanes is known as cracking. Cracking is a process that breaks down long-chain alkanes into shorter-chain alkanes and alkenes.
Statement 3 is also correct. Paraffin wax is a saturated hydrocarbon. It is a white, waxy solid that is made up of long chains of carbon and hydrogen atoms. Paraffin wax is used in a variety of products, including candles, cosmetics, and lubricants.
Therefore, all three statements are correct.