**Core Concept**
Arsenic poisoning is a toxicological emergency caused by excessive ingestion or exposure to arsenic, a naturally occurring element. The symptoms of arsenic poisoning can be acute or chronic, depending on the dose and duration of exposure. In acute arsenic poisoning, the clinical presentation can mimic other conditions, making diagnosis challenging.

**Why the Correct Answer is Right**
Arsenic poisoning can cause gastrointestinal symptoms such as diarrhea, abdominal pain, and vomiting, which are similar to those seen in cholera, a diarrheal disease caused by Vibrio cholerae. The mechanism underlying this similarity lies in the fact that both arsenic and cholera toxin can cause an outpouring of fluid and electrolytes into the intestinal lumen, leading to severe dehydration. Additionally, arsenic can also cause cardiac and neurological symptoms, further confusing the clinical picture.

**Why Each Wrong Option is Incorrect**
**Option B:** Dhatura poisoning typically presents with anticholinergic symptoms such as dry mouth, blurred vision, and hallucinations, which are not characteristic of arsenic poisoning.
**Option C:** Barbiturates poisoning typically presents with CNS depression, including sedation, coma, and respiratory depression, which is not consistent with the symptoms of arsenic poisoning.
**Option D:** Morphine poisoning typically presents with CNS depression, including sedation, respiratory depression, and miosis, which is not consistent with the symptoms of arsenic poisoning.

**Clinical Pearl / High-Yield Fact**
Arsenic poisoning can be diagnosed by analyzing the urine for arsenic or its metabolites, and treatment involves supportive care, including fluid replacement and chelation therapy with agents like dimercaprol.

✓ Correct Answer: A. Cholera