**Core Concept**
Organophosphorous poisoning is a type of cholinergic crisis caused by the inhibition of acetylcholinesterase enzyme, leading to an accumulation of acetylcholine in the synaptic cleft. This results in overstimulation of muscarinic and nicotinic receptors, causing a range of systemic and neuromuscular effects.

**Why the Correct Answer is Right**
Pupillary dilatation is not typically seen in organophosphorous poisoning. Instead, the expected effect is miosis (pupillary constriction) due to the overstimulation of muscarinic receptors in the eye. The inhibition of acetylcholinesterase leads to an excessive release of acetylcholine, which binds to muscarinic receptors in the eye, causing the pupils to constrict. This is in contrast to the expected dilatation seen in opioid intoxication or other conditions.

**Why Each Wrong Option is Incorrect**
**Option B:** Salivation is a characteristic feature of organophosphorous poisoning due to the overstimulation of muscarinic receptors in the salivary glands, leading to increased secretions.
**Option C:** Bronchospasm is also seen in organophosphorous poisoning due to the overstimulation of muscarinic receptors in the airways, leading to bronchoconstriction.
**Option D:** Sweating is another common feature of organophosphorous poisoning, resulting from the overstimulation of muscarinic receptors in the eccrine glands.

**Clinical Pearl / High-Yield Fact**
In organophosphorous poisoning, the use of atropine as an antidote is based on its ability to competitively inhibit muscarinic receptors, reducing the effects of excessive acetylcholine release. This is a critical aspect of management in cases of cholinergic crisis.

**✓ Correct Answer: A. Pupillary dilatation**