This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroanatomy, Head and Neck, Subject name: Anatomy
66-year-old woman is unable to open her mouth or jaw because of tetanus resulting from a penetrating wound from a rusty nail. Which of the following muscles would most likely be paralyzed? 
Select and explain. 
A. A, B. B, C. C, D. D
B: B
Answer: B: B 
Explanation: Lateral pterygoid muscle opens the mouth by depressing the jaw. Masseter, medial pterygoid, and temporalis muscles close the jaw. Buccinator muscle is a muscle of facial expression.