**Core Concept**
Bence Jones proteins are abnormal immunoglobulin light chains that are excreted in the urine due to their small size, which allows them to be filtered through the glomeruli and excreted in the urine. This phenomenon is commonly seen in multiple myeloma and other plasma cell dyscrasias.

**Why the Correct Answer is Right**
Bence Jones proteins are composed of either kappa or lambda light chains, which are produced in excess by the malignant plasma cells in multiple myeloma. These light chains are not recombined with heavy chains, making them smaller and more prone to renal excretion. The presence of Bence Jones proteins in the urine is a diagnostic hallmark of multiple myeloma and other plasma cell dyscrasias.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Bence Jones proteins are not a type of normal immunoglobulin. They are abnormal light chains that are produced in excess by malignant plasma cells.
**Option B:** This option is incorrect because Bence Jones proteins are not a type of protein that is associated with liver disease. They are specifically associated with plasma cell dyscrasias such as multiple myeloma.
**Option C:** This option is incorrect because Bence Jones proteins are not a type of protein that is associated with acute kidney injury. While they can be a sign of renal impairment, they are not a direct cause of acute kidney injury.

**Clinical Pearl / High-Yield Fact**
The presence of Bence Jones proteins in the urine is a diagnostic hallmark of multiple myeloma and other plasma cell dyscrasias. It is essential to note that Bence Jones proteins can also be seen in other conditions such as monoclonal gammopathy of undetermined significance (MGUS) and Waldenström's macroglobulinemia.

**Correct Answer: A. Abnormal immunoglobulin light chains.**