This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Following modification occurs in Gs subunit which leads to watery diarrhea in cholera \nSelect and explain. \nA. ADP ribosylation, B. ATP-ADP transfer, C. Phosphorylation, D. Dephosphorylation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. ADP ribosylation', 'role': 'assistant'}]