**Core Concept**
CHCs (Community Health Centres) are a type of primary healthcare facility in India, established to provide comprehensive healthcare services to rural and underserved areas. They act as a referral center for the surrounding Primary Health Centres (PHCs) and are responsible for providing specialized care and services.

**Why the Correct Answer is Right**
CHCs serve as a referral center for PHCs, which are the first point of contact for rural populations. When a patient requires specialized care, they are referred to the CHC, which has a more comprehensive range of services and specialists. This referral system allows for timely and appropriate management of complex cases. CHCs also provide training and supervision to PHC staff, ensuring that they are equipped to provide high-quality primary care.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a correct answer as CHCs do not typically serve as referral centers for other types of healthcare facilities.
**Option B:** This option is incorrect as CHCs are not primarily responsible for providing emergency services, although they may have some emergency facilities.
**Option C:** This option is not accurate as CHCs are not typically responsible for providing tertiary care services, which are typically provided by larger hospitals.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that CHCs play a critical role in the referral system of rural healthcare in India, and understanding their role is crucial for effective healthcare planning and management.

**Correct Answer:** D.