**Core Concept**
Leprosy, also known as Hansen's disease, is a chronic bacterial infection caused by Mycobacterium leprae. Its duration and progression are crucial for effective management and prevention of complications.

**Why the Correct Answer is Right**
The correct answer refers to the incubation period of leprosy, which is the time from exposure to the bacteria to the onset of symptoms. The incubation period of leprosy is typically 3-5 years, but it can range from 1-20 years. In this context, 2 years is mentioned, which falls within the possible range of incubation periods.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable, as the question does not specify the type of duration (e.g., incubation, treatment, or relapse).
**Option B:** Not relevant, as the question is about the duration of leprosy, not its symptoms or complications.
**Option C:** Not correct, as the question specifically asks about the duration of leprosy, not its transmission or epidemiology.

**Clinical Pearl / High-Yield Fact**
The World Health Organization (WHO) recommends a 12-month multidrug therapy regimen for the treatment of leprosy. Early detection and treatment can prevent disability and complications.

**Correct Answer:** C.