This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria), Subject name: Microbiology
[{'content': 'Mechanism of action of cholera toxin is through: \nSelect and explain. \nA. Gangliosides, B. Adenyl cyclase, C. Gangliosides + adenyl cyclase, D. Exotoxin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cholera enterotoxin Light toxin: binds with ganglioside in epithelial cell membrane Heavy toxin: activates adenyl cyclase in epithelial cell wall which increase cAMP, leading to outpouring of isotonic fluid in lumen of intestine', 'role': 'assistant'}]