## Core Concept
The transformation of Chronic Lymphocytic Leukemia (CLL) or Small Lymphocytic Lymphoma (SLL) into Diffuse Large B-Cell Lymphoma (DLBCL) refers to a process where a more indolent lymphoma transforms into a more aggressive form. This process involves a change in the biological behavior of the lymphoma, often associated with a worse prognosis.

## Why the Correct Answer is Right
The correct term for this transformation is **Richter transformation**. It is a clinical syndrome where CLL or SLL transforms into a more aggressive lymphoma, typically DLBCL. This transformation is characterized by a rapid increase in symptoms, often including fever, weight loss, and an enlarging lymph node or spleen. The transformation involves a genetic evolution of the lymphoma cells, which can include mutations or changes in gene expression that lead to a more aggressive phenotype.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is blank and does not provide any relevant information.
- **Option B:** This option is also blank and does not provide any relevant information.
- **Option C:** This option does not specify the correct term for the transformation of CLL/SLL into DLBCL.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that Richter transformation is associated with a poor prognosis and often requires a change in treatment strategy, typically involving more aggressive chemotherapy regimens. Clinicians should be vigilant for signs of transformation, such as a sudden increase in lymph node size or the development of systemic symptoms.

## Correct Answer Line
**Correct Answer: D. Richter transformation.**