## Core Concept
The National Leprosy Eradication Programme (NLEP) is a health initiative aimed at eliminating leprosy, a chronic bacterial infection caused by *Mycobacterium leprae*, which primarily affects the skin, nerves, and mucous membranes. Leprosy, also known as Hansen's disease, is a significant public health concern in many developing countries, including India. The program's primary goal is to detect cases early, provide treatment, and prevent disabilities.

## Why the Correct Answer is Right
The National Leprosy Eradication Programme was launched in 1983 by the Government of India. This initiative was a response to the significant burden of leprosy in the country and the need for a comprehensive approach to control and eliminate the disease. The program involves multidrug therapy (MDT) for patients, which has been highly effective in curing leprosy and preventing drug resistance. The year 1983 marks the beginning of a concerted national effort to tackle leprosy through a structured program.

## Why Each Wrong Option is Incorrect
- **Option A:** 1985 - This is incorrect because the NLEP was started two years earlier, in 1983.
- **Option B:** 1990 - This option is also incorrect as it is seven years after the actual launch of the program.
- **Option D:** 1975 - This is incorrect because it predates the actual launch of the NLEP by eight years.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the NLEP was launched in 1983, and it has been instrumental in reducing the prevalence of leprosy in India. The program's success is attributed to its strategy of using multidrug therapy, which has been provided free of cost to all patients. This initiative has not only treated millions of patients but also helped in reducing the stigma associated with the disease.

## Correct Answer: C. 1983.