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: Anatomy
Which muscle divides the neck into anterior and posterior triangles? 
Select and explain. 
A. Sternomastoid, B. Platysma, C. Digastric, D. Trapezius
A: Sternomastoid
Answer: A: Sternomastoid 
Explanation: None