**Core Concept**
Non-Hodgkin's lymphoma (NHL) is a heterogeneous group of malignancies arising from lymphoid cells. It is classified based on the World Health Organization (WHO) classification system, which categorizes NHL into several subtypes based on morphological, immunophenotypic, and genetic features. The intermediate form of NHL typically exhibits features that are intermediate between low-grade and high-grade lymphomas.

**Why the Correct Answer is Right**
The intermediate form of NHL, also known as diffuse, small cleaved cell lymphoma, is characterized by a mixture of small, cleaved cells and larger, more pleomorphic cells. This subtype typically expresses B-cell markers such as CD20 and CD79a, and often shows a clonal immunoglobulin heavy chain gene rearrangement. The diffuse, small cleaved cell lymphoma is considered an intermediate-grade lymphoma because it tends to have a moderate growth fraction and a moderate level of cytological atypia.

**Why Each Wrong Option is Incorrect**
**Option A:** Small noncleaved cell lymphoma is a high-grade subtype of NHL that typically consists of large, round cells with a high nuclear-to-cytoplasmic ratio. It is characterized by a high proliferation rate and is often associated with a poor prognosis.

**Option C:** Lymphoblastic lymphoma is a highly aggressive subtype of NHL that typically consists of immature lymphoblasts. It is often associated with a high proliferation rate and is considered a high-grade lymphoma.

**Option D:** Large cell immunoblastic lymphoma is a high-grade subtype of NHL that typically consists of large, pleomorphic cells with a high nuclear-to-cytoplasmic ratio. It is characterized by a high proliferation rate and is often associated with a poor prognosis.

**Clinical Pearl / High-Yield Fact**
The WHO classification system for NHL is an essential tool for pathologists and clinicians to accurately diagnose and manage patients with NHL. The classification system takes into account the morphological, immunophenotypic, and genetic features of the lymphoma, and helps to predict the prognosis and treatment response.

**✓ Correct Answer: B. Diffuse, small cleaved cell**