## Core Concept
The central anticholinergic effect, also known as anticholinergic syndrome, is a condition caused by blockade of muscarinic receptors in the central nervous system. This can lead to symptoms such as confusion, delirium, hallucinations, and in severe cases, coma. The treatment involves administering a drug that can counteract these effects.

## Why the Correct Answer is Right
Physostigmine is a cholinesterase inhibitor that can cross the blood-brain barrier, making it effective in treating central anticholinergic effects. By inhibiting acetylcholinesterase, the enzyme responsible for the breakdown of acetylcholine, physostigmine increases the concentration of acetylcholine in the synaptic cleft, thereby enhancing cholinergic transmission and counteracting the central anticholinergic syndrome.

## Why Each Wrong Option is Incorrect
* **Option A:** Flumazenil is a benzodiazepine receptor antagonist used to treat benzodiazepine overdoses, not central anticholinergic effects.
* **Option B:** Naloxone is an opioid receptor antagonist used to counteract life-threatening depression of the central nervous system and respiratory system, not central anticholinergic effects.
* **Option D:** Neostigmine is a cholinesterase inhibitor but does not effectively cross the blood-brain barrier, making it ineffective for treating central anticholinergic effects.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that physostigmine is specifically used for treating severe anticholinergic toxicity that affects the central nervous system. However, its use is limited due to potential side effects, such as bradycardia and bronchospasm, and it should be administered in a monitored setting.

## Correct Answer: C. Physostigmine.