**Core Concept**
Neurolathyrism is a rare neurodegenerative disorder caused by the consumption of the Lathyrus sativus legume, particularly during times of famine or food scarcity. It is characterized by lower limb weakness, spasticity, and atrophy due to the ingestion of a toxin present in the plant.

**Why the Correct Answer is Right**
The toxin responsible for neurolathyrism is a non-protein amino acid called ODAP (oxalyldiaminopropionic acid). ODAP acts as a glutamate antagonist by inhibiting the activity of glutamate receptors, specifically the N-methyl-D-aspartate (NMDA) receptors, in the spinal cord and brain. This inhibition leads to an imbalance in the excitatory and inhibitory neurotransmitter systems, resulting in the characteristic neurological symptoms of neurolathyrism.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because this option does not specify the toxin responsible for neurolathyrism.
**Option B:** Incorrect because this option does not mention the specific mechanism of action of the toxin, which is crucial for understanding the pathophysiology of neurolathyrism.
**Option C:** Incorrect because this option is a distractor that does not relate to the causative agent of neurolathyrism.

**Clinical Pearl / High-Yield Fact**
Neurolathyrism is a classic example of a neurotoxic disorder caused by the consumption of a specific plant, highlighting the importance of dietary awareness and food safety in preventing such conditions.

**Correct Answer:** D. ODAP (oxalyldiaminopropionic acid)