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': 'Tetany is characterised by: \nSelect and explain. \nA. Hypotonicity of muscles, B. Hypertonicity of muscles, C. Increased serum calcium concentration, D. None of above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]