**Core Concept**
Paracetamol (acetaminophen) overdose is a common cause of acute liver failure, leading to coagulopathy, encephalopathy, and potentially death if not treated promptly. The treatment involves the administration of activated charcoal, N-acetylcysteine (NAC), and supportive care.

**Why the Correct Answer is Right**
N-acetylcysteine (NAC) is the treatment of choice for paracetamol overdose due to its ability to replenish glutathione stores in the liver, thereby preventing the formation of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI). NAC also has antioxidant properties, which help to reduce liver damage. The administration of NAC should ideally start within 8-10 hours of ingestion, but it can be effective even if started later.

**Why Each Wrong Option is Incorrect**
* **Option A:** Activated charcoal is useful for reducing absorption of ingested toxins, but it is not the primary treatment for paracetamol overdose.
* **Option B:** Supportive care, such as hydration and monitoring, is crucial in managing paracetamol overdose, but it is not the specific treatment of choice.
* **Option C:** Methionine is sometimes used as a antidote for paracetamol overdose, but NAC is the preferred treatment due to its better efficacy and safety profile.

**Clinical Pearl / High-Yield Fact**
The Rumack-Matthew nomogram can be used to estimate the risk of liver damage based on the time elapsed since ingestion and the dose of paracetamol taken. This can help guide the decision to administer NAC.

**Correct Answer: C. N-acetylcysteine (NAC).**