The correct answer is D. Ethylene.
Ethylene is a colorless, flammable gas that is the simplest alkene. It is the most produced organic chemical in the world, with an annual production of over 100 million tons. Ethylene is used to produce a wide variety of products, including polyethylene, polypropylene, ethylene glycol, and ethylene oxide.
Polyethylene is a type of plastic that is made from ethylene. It is the most common type of plastic in the world, and it is used to make a wide variety of products, including bags, bottles, toys, and pipes.
The polymerization of ethylene is a process in which ethylene molecules are joined together to form long chains. These chains are then arranged into a crystalline structure, which gives polyethylene its strength and durability.
The polymerization of ethylene is a very important industrial process, and it is used to produce a wide variety of products. Ethylene is a relatively inexpensive raw material, and it is easy to polymerize. This makes it an ideal material for the production of plastics.
The other options are incorrect because they are not used in the manufacturing of polythene in industry. Methane is a gas that is used as a fuel. Styrene is a liquid that is used to produce polystyrene. Acetylene is a gas that is used to produce acetylene gas.