**Core Concept**
Suxamethonium (succinylcholine) is a depolarizing neuromuscular blocking agent that induces apnea by activating nicotinic acetylcholine receptors (nAChRs) on the motor end-plate, leading to persistent depolarization and muscle paralysis.

**Why the Correct Answer is Right**
The prolonged apnea after suxamethonium administration is primarily due to the accumulation of suxamethonium and its metabolites, which competitively inhibit acetylcholinesterase, the enzyme responsible for breaking down acetylcholine. This results in a continuous activation of nAChRs, maintaining muscle paralysis. The normal duration of action of suxamethonium is approximately 4-6 minutes, and prolonged apnea beyond this period suggests an abnormal response, such as suxamethonium apnea syndrome.

**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.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
Suxamethonium apnea syndrome is a rare but life-threatening condition that requires prompt recognition and management. It is essential to consider this diagnosis in patients with prolonged apnea after suxamethonium administration and to initiate supportive care, including mechanical ventilation and cardiac monitoring.

**Correct Answer: Not Provided**