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: Pathology
'Lock jaw' indicates 
Select and explain. 
A. Ankylosis, B. Spasm of masseter muscle, C. Inflammatory trismus, D. Fracture of condyle
B: Spasm of masseter muscle
Answer: B: Spasm of masseter muscle 
Explanation: None