**Core Concept**
Polychlorinated hydrocarbons (PCHs) are a class of synthetic organic compounds that contain multiple chlorine atoms bonded to a hydrocarbon framework. They are known for their stability, non-polarity, and lipophilicity, which makes them resistant to degradation and allows them to bioaccumulate in the environment and living organisms.

**Why the Correct Answer is Right**
The correct answer is a type of PCH that is commonly used as a insecticide, due to its high potency and long-lasting effects. It works by inhibiting the action of acetylcholinesterase, an enzyme crucial for the breakdown of the neurotransmitter acetylcholine, leading to an accumulation of acetylcholine in the synapse and overstimulation of muscles and glands. This results in symptoms such as tremors, muscle weakness, and paralysis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a type of PCH used as a herbicide, not an insecticide. While it is also a well-known PCH, its mechanism of action and clinical effects differ from the correct answer.
**Option B:** This option is incorrect because it is a type of PCH used as a solvent and degreaser, not an insecticide. It is not known for its insecticidal properties and is not a member of the same class as the correct answer.
**Option C:** This option is incorrect because it is a type of PCH used as a fire retardant, not an insecticide. While it is a stable and non-polar compound, its primary use is in fire safety applications, not as an insecticide.

**Clinical Pearl / High-Yield Fact**
PCHs, including the correct answer, can cause a range of systemic and neurological effects, including tremors, muscle weakness, and paralysis, due to their inhibition of acetylcholinesterase. This is a classic example of a cholinergic toxicity, which can be reversed with administration of acetylcholinesterase inhibitors such as atropine and pralidoxime.

**Correct Answer: B. DDT (Dichlorodiphenyltrichloroethane)**