**Core Concept**
Chain referral is a public health strategy used to identify and track individuals with sexually transmitted diseases (STDs) by asking patients to name other members of their socio-sexual network, who are then investigated for potential infection.

**Why the Correct Answer is Right**
This approach is based on the principle that individuals with STDs often have multiple sexual partners and are part of a larger network of individuals at risk. By identifying and investigating these networks, public health officials can effectively prevent the spread of STDs and target high-risk populations for education and treatment. Chain referral is particularly useful in areas with limited resources, as it allows public health officials to maximize their efforts by identifying and tracking individuals who are most likely to be at risk.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the chain referral method, which specifically involves asking patients to name other members of their socio-sexual network.
**Option B:** This option is incorrect because it is a vague term that does not accurately describe the chain referral method.
**Option C:** This option is incorrect because it is a different public health strategy that involves providing incentives for individuals to participate in STD testing and reporting.

**Clinical Pearl / High-Yield Fact**
Chain referral is a key component of public health efforts to control the spread of STDs, particularly in areas with limited resources.

**Correct Answer: C. Contact tracing.