**Core Concept**
The question pertains to the identification and characteristics of plant irritants, specifically those used as poison or toxins. These substances can cause various systemic effects due to their pharmacological properties, and knowledge of their clinical manifestations is crucial in forensic medicine.

**Why the Correct Answer is Right**
The correct answer is A, as Abrus precatorius does not resemble cobra snake bite upon ingestion. Cobra snake bite is characterized by the presence of neurotoxins, which cause respiratory failure, paralysis, and eventually death. Abrus precatorius, on the other hand, contains the toxin abrin, which is a potent inhibitor of protein synthesis and causes gastrointestinal symptoms, renal failure, and hemorrhage upon ingestion. The symptoms of Abrus precatorius poisoning are more akin to those of a gastrointestinal toxin rather than a neurotoxin like cobra snake bite.

**Why Each Wrong Option is Incorrect**
**Option B:** Nux vomica indeed contains the toxin strychnine, which is a potent neurotoxin that acts on the central nervous system, causing muscle convulsions and death. This statement is true.
**Option C:** Strychnine poisoning is often associated with the plant Strychnos nux-vomica, but Abrus precatorius, also known as rosary pea or crab's eye, is indeed involved in a practice called "sui-picking," where the seeds are used as a poison. This statement is true.
**Option D:** Ricinus communis, commonly known as the castor oil plant, contains ricin, a toxin that can cause gastrointestinal symptoms, renal failure, and hemorrhage upon ingestion. Ricin's mechanism of action is similar to that of Abrus precatorius, and it can produce a cholera-like action due to its ability to cause severe diarrhea and dehydration. This statement is true.

**Clinical Pearl / High-Yield Fact**
When encountering plant irritants in forensic medicine, it is essential to note that each plant has unique characteristics and symptoms associated with its toxin. Familiarity with these characteristics can aid in identifying the plant and potentially saving lives.

**✓ Correct Answer: A. Abrus ingestion resembles cobra snake bite.**