**Core Concept**
Paucibacillary leprosy is a form of leprosy characterized by few skin lesions and minimal bacterial load. The World Health Organization (WHO) recommends a multidrug therapy (MDT) regimen for its treatment.

**Why the Correct Answer is Right**
The WHO MDT regimen for paucibacillary leprosy consists of rifampicin and dapsone for 6 months. This duration is crucial to ensure that the bacteria are effectively eliminated, and the patient is cured. Rifampicin is a potent bactericidal agent that targets the bacterial cell wall, while dapsone is a bacteriostatic agent that inhibits bacterial growth. The combination of these two drugs is essential to prevent the development of drug resistance.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, but the correct answer will be provided below.
* **Option B:** This option is incorrect because the WHO MDT regimen for paucibacillary leprosy is not 9 months.
* **Option C:** This option is incorrect because the WHO MDT regimen for paucibacillary leprosy is not 12 months.
* **Option D:** This option is incorrect because the WHO MDT regimen for paucibacillary leprosy is not 18 months.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the WHO MDT regimen for paucibacillary leprosy is shorter than that for multibacillary leprosy, which requires 12 months of treatment.

**Correct Answer:** C. 6 months