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, 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 is used to make a wide variety of products, including bags, bottles, and pipes.
The polymerization of ethylene is a chemical reaction in which many ethylene molecules are joined together to form a long chain. This reaction is catalyzed by a metal catalyst, such as Ziegler-Natta catalyst.
The polymerization of ethylene is a very important industrial process, and is used to produce a wide variety of products.