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': 'The emeiocytosis or reverse pinocytosis requires which ion \nSelect and explain. \nA. Na+, B. K+, C. Ca++, D. Mg++', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Ca++', 'role': 'assistant'}]