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
Tetany is characterised by: 
Select and explain. 
A. Hypotonicity of muscles, B. Hypertonicity of muscles, C. Increased serum calcium concentration, D. None of above
B: Hypertonicity of muscles
Answer: B: Hypertonicity of muscles 
Explanation: None