**Core Concept**
The underlying principle being tested is the metabolism of amino acids, specifically the catabolic pathway of histidine. This process involves the breakdown of histidine into various intermediate compounds.

**Why the Correct Answer is Right**
The correct answer is related to the fact that histidine metabolism leads to the formation of formiminoglutamic acid (FIGLU), an intermediate in the catabolic pathway. This occurs through the action of the enzyme histidine ammonia-lyase, which converts histidine into formiminoglutamate.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the metabolism of this amino acid does not lead to the formation of FIGLU.
**Option B:** Similarly, this option is incorrect as it is not associated with FIGLU production.
**Option D:** This option is also incorrect because its metabolic pathway does not involve the production of FIGLU.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that elevated levels of FIGLU in the urine can be an indicator of folic acid deficiency, as folate is required for the further metabolism of FIGLU.

**Correct Answer:** C. Histidine