**Core Concept**
Hodgkin's lymphoma is a type of lymphoma characterized by the presence of Reed-Sternberg cells. The disease often presents with lymphadenopathy, which can be systemic or localized. In Hodgkin's lymphoma, the lymph nodes are typically involved in a predictable pattern, with certain sites being more commonly affected than others.

**Why the Correct Answer is Right**
The most common site of lymph node enlargement in Hodgkin's lymphoma is the cervical lymph nodes. This is because the disease often originates in the lymphoid tissues of the neck, including the lymph nodes of the cervical chain. The disease then progresses to involve other lymph node groups in an orderly fashion, typically following the path of lymphatic drainage. The involvement of the cervical lymph nodes is a hallmark of Hodgkin's lymphoma and is often the presenting feature of the disease.

**Why Each Wrong Option is Incorrect**
* **Option A:** The axillary lymph nodes can be involved in Hodgkin's lymphoma, but they are not the most common site of enlargement.
* **Option B:** The inguinal lymph nodes are not typically involved in the early stages of Hodgkin's lymphoma.
* **Option D:** The mediastinal lymph nodes can be involved in Hodgkin's lymphoma, but they are not the most common site of enlargement.

**Clinical Pearl / High-Yield Fact**
The involvement of the cervical lymph nodes in Hodgkin's lymphoma is often accompanied by systemic symptoms such as fever, night sweats, and weight loss. These symptoms are known as B symptoms and are an important prognostic factor in the disease.

**Correct Answer: B. Cervical lymph nodes.**