**Core Concept**
The Revised National Tuberculosis Control Programme (RNTCP) is a key initiative by the Government of India to control tuberculosis (TB) in the country. The program focuses on early case detection and treatment to prevent the spread of TB. Case finding is a crucial aspect of RNTCP, involving the identification of TB patients in the community.

**Why the Correct Answer is Right**
RNTCP case finding primarily relies on a system of sputum smear microscopy and chest X-rays to diagnose pulmonary TB. The program also uses a system of active case finding, where health workers visit households and communities to identify TB patients. This approach helps in early detection and treatment of TB patients, reducing the risk of transmission to others. The program also emphasizes the use of contact tracing to identify individuals who have been in close contact with TB patients.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not describe the primary method of case finding in RNTCP.
**Option B:** This option is incorrect as it does not accurately describe the case finding strategy used by RNTCP.
**Option C:** This option is incorrect as it is not a recognized method of case finding in RNTCP.

**Clinical Pearl / High-Yield Fact**
RNTCP case finding emphasizes the importance of early detection and treatment of TB to prevent the spread of the disease. The program's focus on active case finding and contact tracing has helped in reducing the incidence of TB in India.

**Correct Answer:** B. Active case finding and sputum smear microscopy.