**Core Concept**
Fish odour syndrome, also known as trimethylaminuria (TMAU), is a rare genetic disorder characterized by the inability to metabolize trimethylamine (TMA), a compound found in fish and other foods. This leads to a strong, unpleasant body odor.

**Why the Correct Answer is Right**
The correct answer is **Vitamin B6**. The enzyme flavin-containing monooxygenase 3 (FMO3) is responsible for converting TMA into its non-volatile metabolites. Vitamin B6 acts as a cofactor for FMO3, facilitating the breakdown of TMA and reducing its concentration in the body. Supplementation with Vitamin B6 has been studied as a potential treatment for TMAU, although its efficacy can vary depending on the individual and the severity of their condition.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the treatment of Fish odour syndrome.
* **Option B:** While certain medications may be used to manage symptoms of TMAU, there is no established role for this option in treating the underlying condition.
* **Option D:** This option is not a recognized treatment for Fish odour syndrome.

**Clinical Pearl / High-Yield Fact**
When managing patients with TMAU, it's essential to note that dietary changes, such as avoiding fish and other high-TMA foods, can help alleviate symptoms. However, these measures may not completely eliminate the odor, and pharmacological interventions like Vitamin B6 supplementation may be necessary.

**Correct Answer:** C.