PCB stands for __________.

• A. Polychlorinated Biphenyls
• B. Polycarbonate Biphenyls
• C. Polychlorinated Butylphenyls
• D. Polyphenyl Biphenyls

Answer: (A)

PCB stands for polychlorinated biphenyls. Here, polychlorinated means many chlorine atoms are attached to the biphenyl structure, which is two benzene rings connected together. This naming describes a family of synthetic chlorinated hydrocarbons that were commonly used as dielectric fluids and coolants in electrical equipment because they are chemically stable and nonflammable. However, they are highly persistent in the environment and pose health risks, leading to bans and strict controls in many places.

Other options don’t fit because they either describe a different chemical class (for example, a polycarbonate polymer) or use an uncommon or incorrect substituent (such as butylphenyl), or omit the chlorine component that defines the compound family.