The correct answer is A. Formaldehyde.
Bakelite is a thermosetting plastic made from phenol and formaldehyde. It was the first commercially successful plastic and is still used today in a variety of applications, including electrical insulation, cookware, and jewelry.
Formaldehyde is a colorless, flammable gas with a strong, pungent odor. It is used in the production of many products, including Bakelite, plastics, resins, and adhesives. It is also used in some medical treatments, such as embalming and cancer therapy.
Acetaldehyde is a colorless, flammable liquid with a fruity odor. It is used in the production of many products, including vinegar, plastics, and pharmaceuticals. It is also used as a solvent and in some industrial processes.
Benzaldehyde is a colorless, flammable liquid with a almond-like odor. It is used in the production of many products, including perfumes, flavorings, and pharmaceuticals. It is also used as a solvent and in some industrial processes.
Cinnaldehyde is a yellow, oily liquid with a cinnamon-like odor. It is used in the production of many products, including perfumes, flavorings, and pharmaceuticals. It is also used as a solvent and in some industrial processes.
In conclusion, the correct answer is A. Formaldehyde.