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: Pharmacology
[{'content': 'Which of the following is not a hydrophobic secondary messenger? \nSelect and explain. \nA. DAG, B. IP3, C. Phosphatidyl inositol, D. cAMP', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]