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
[{'content': 'Upper boundary of quadrangular space is formed by: \nSelect and explain. \nA. Teres major, B. Teres minor, C. Long head of triceps, D. Surgical neck of humerus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Boundaries of quadrangular spaceAbove/superior: the subscapularis and teres minorBelow/inferior: the teres majorMedially: the long head of the triceps brachiiLaterally: the surgical neck of humerus', 'role': 'assistant'}]