This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hand, Subject name: Anatomy
[{'content': 'Insertion of extensor carpi ulnaris \nSelect and explain. \nA. Base of proximal phalanx of thumb, B. Base of Distal phalanx of thumb, C. Base of 5th Metacarpal, D. Scaphoid base', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Base of 5th MetacarpalExtensor carpi ulnariso Origin : Lateral epicondyle of humerus and posterior border ulnao Insertion : Base of 5th metacarpalo Nerve supply : Posterior interosseus nerveo Action : Extension (dorsiflexion) and adduction of hand.", 'role': 'assistant'}]