This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lower limb 1, Subject name: Anatomy
[{'content': 'Which of the following forms medial boundary of the marked structure \nSelect and explain. \nA. Lacunar ligament, B. Inguinal ligament, C. Femoral vein, D. Pectineus muscle', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Marked structure - Femoral ring Boundaries of Femoral ring Medially - Lacunar ligament Laterally - Femoral vein Anterior - Inguinal ligament Posterior - Pectineus', 'role': 'assistant'}]