**Core Concept**
Organophosphorus poisoning is a medical emergency caused by the inhibition of acetylcholinesterase, leading to an accumulation of acetylcholine in the nervous system. This results in excessive stimulation of muscarinic and nicotinic receptors, causing a range of systemic effects.

**Why the Correct Answer is Right**
Atropine and pralidoxime (2-PAM) are the mainstays of treatment for organophosphorus poisoning. Atropine works by competitively inhibiting the action of acetylcholine at muscarinic receptors, thereby reducing the severity of symptoms such as bradycardia, bronchospasm, and excessive salivation. Pralidoxime, on the other hand, reactivates acetylcholinesterase by breaking the covalent bond between the enzyme and the organophosphate molecule.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
In organophosphorus poisoning, the use of atropine is most effective when given early in the course of the poisoning, as delayed treatment can lead to irreversible damage to the nervous system.

**Correct Answer: A.**