A patient presents with acute onset of severe watery diarrhea, described as 'rice-water stools,' without fever or significant abdominal pain. The causative bacterium produces a toxin that permanently activates adenylate cyclase. Which organism is most likely responsible?
✓ Correct Answer: Option C
Vibrio cholerae produces cholera toxin, which irreversibly activates adenylate cyclase via ADP-ribosylation of the Gs protein, leading to excessive fluid secretion into the gut lumen and 'rice-water stools'.