**Core Concept:** Carbon monoxide (CO) is a colorless, odorless, and tasteless gas produced by incomplete combustion of carbon-containing fuels. It binds to hemoglobin (Hb) and methemoglobin (metHb), reducing oxygen transport and leading to tissue hypoxia and multiorgan dysfunction. Death from CO poisoning occurs due to severe cerebral and myocardial hypoxia, leading to cardiac arrest and neurological dysfunction.

**Why the Correct Answer is Right:** The correct answer is C, which states a feature of death due to CO poisoning is "cardiac arrest." This is because CO poisoning causes severe cerebral and myocardial hypoxia due to the carbon monoxide's affinity for hemoglobin (Hb) and methemoglobin (metHb), reducing oxygen transport. This results in multiorgan dysfunction, including cardiac arrest, as the heart cannot receive sufficient oxygen to function properly.

**Why Each Wrong Option is Incorrect:**
A. "Respiratory distress" is a symptom of CO poisoning, not a feature of death due to it.
B. "Multiorgan dysfunction" is a consequence of CO poisoning but not a feature of death caused by it.
D. "Sudden cardiac arrest" is not specific to CO poisoning; it can occur due to various causes unrelated to CO poisoning.

**Clinical Pearl:**
A child's death following a fire accident involving CO poisoning should raise suspicion for this cause, as it is often an overlooked cause of sudden death, particularly in cases with no apparent mechanism. Early recognition of CO poisoning is crucial for prompt treatment, which includes evacuation to a well-ventilated area, administration of oxygen therapy, and referral for further management.

**Correct Answer:** C. "Cardiac arrest" is a feature of death due to CO poisoning. Death from CO poisoning occurs due to severe cerebral and myocardial hypoxia caused by CO's affinity for hemoglobin and methemoglobin, impairing oxygen transport. This leads to multiorgan dysfunction and, in severe cases, cardiac arrest.