## Core Concept
Multiple myeloma is a type of hematological malignancy characterized by the proliferation of malignant plasma cells in the bone marrow. This condition leads to various complications, including anemia, bone lesions, and the production of abnormal proteins. One of the hallmark features of multiple myeloma is the presence of **Bence Jones proteins**, which are free light chains of immunoglobulins.

## Why the Correct Answer is Right
The correct answer, **Bence Jones proteins**, are seen in multiple myeloma because these proteins are produced by malignant plasma cells. In normal conditions, plasma cells produce complete immunoglobulins, but in multiple myeloma, there is an overproduction of light chains, which can be detected in the urine as Bence Jones proteins. The detection of these proteins is a diagnostic criterion for multiple myeloma.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it does not specify a known association with multiple myeloma.
- **Option B:** This option is incorrect as it does not accurately represent a characteristic feature of multiple myeloma.
- **Option C:** This option might relate to other conditions or is not specific to multiple myeloma.

## Clinical Pearl / High-Yield Fact
A key clinical pearl for multiple myeloma is that **Bence Jones proteins** can be detected in the urine of approximately 60-70% of patients with multiple myeloma. The detection of these proteins is facilitated by **urine protein electrophoresis** or **immunofixation electrophoresis**. This finding is crucial for the diagnosis and monitoring of multiple myeloma.

## Correct Answer: B. Bence Jones proteins.