The correct answer is A. ethylene.
Polyethylene is a type of plastic that is made from the monomer ethylene. Ethylene is a gas that is produced by the cracking of petroleum. It is then polymerized to form polyethylene. Polyethylene is a versatile material that is used in a variety of products, including bags, bottles, and pipes.
Propylene is another type of plastic that is made from the monomer propylene. Propylene is a gas that is also produced by the cracking of petroleum. It is then polymerized to form polypropylene. Polypropylene is a strong and lightweight material that is used in a variety of products, including car parts, furniture, and toys.
Acetylene is a gas that is used in welding and cutting. It is also used to produce other chemicals, such as acetaldehyde and acetic acid. Acetylene is not a polymer.
Aniline is a liquid that is used to produce dyes and other chemicals. It is also used as a solvent. Aniline is not a polymer.