**Core Concept**
Sorghum contains a naturally occurring compound that can lead to a condition similar to pellagra, a disease caused by a deficiency of vitamin B3 (niacin). This condition is known as pellagragenic.

**Why the Correct Answer is Right**
The correct answer is **lysine**, an amino acid. Sorghum contains high levels of lysine, which can interfere with the metabolism of tryptophan, an essential amino acid. Tryptophan is converted into niacin in the body, and when lysine is present in excess, it can inhibit this conversion, leading to a niacin deficiency and potentially causing a pellagra-like condition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the pellagragenic effects of sorghum.
**Option B:** While sorghum is indeed a cereal, this option does not specifically address the pellagragenic compound.
**Option C:** Tryptophan is actually an essential amino acid, but it is not the compound responsible for the pellagragenic effects of sorghum.

**Clinical Pearl / High-Yield Fact**
It's essential to note that pellagra is a disease caused by a deficiency of vitamin B3 (niacin), and it can be prevented by consuming foods rich in niacin or its precursors, such as tryptophan.

**Correct Answer:** D. Lysine