**Core Concept**
Datura poisoning is a type of anticholinergic toxicity caused by the ingestion of plants from the Datura genus, which contain tropane alkaloids such as scopolamine and hyoscine. These compounds act as competitive antagonists at muscarinic acetylcholine receptors, leading to a range of systemic effects.

**Why the Correct Answer is Right**
Pin-point pupils are actually characteristic of muscarinic agonism (e.g., organophosphate poisoning), not anticholinergic toxicity. In Datura poisoning, the muscarinic receptors are blocked, resulting in mydriasis (pupil dilation) rather than miosis (pin-point pupils). This is due to the inhibition of the parasympathetic nervous system's effect on the iris sphincter muscle. The correct answer is pin-point pupils, which is the opposite of what is expected in Datura poisoning.

**Why Each Wrong Option is Incorrect**
**Option A:** Delirium is a characteristic of Datura poisoning, as the anticholinergic effects lead to altered mental status, confusion, and disorientation.
**Option B:** Diplopia (double vision) is also a common symptom of Datura poisoning, resulting from the anticholinergic effects on the muscles controlling eye movements.
**Option D:** Dysphagia (difficulty swallowing) is another characteristic symptom, caused by the anticholinergic effects on the muscles of the pharynx and esophagus.

**Clinical Pearl / High-Yield Fact**
Remember, anticholinergic toxicity (e.g., Datura poisoning) is associated with mydriasis (pupil dilation), not miosis (pin-point pupils). This is a classic exam trap, and it's essential to distinguish between these two opposing effects.

**✓ Correct Answer:** C. Pin-point pupils