This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
[{'content': 'The main muscle of opposition is? \nSelect and explain. \nA. Abductor pollicis brevis, B. Flexor pollicis brevis, C. Opponens pollicis, D. Adductor pollicis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Opponens pollicis - Origin-flexor retinaculum crest of trapezium Inseion- lateral border and adjoining lateral half of planar surface of the 1 St metacarpal bone Actions- Opposition of thumb & deepens the hollow of palm Abductor pollicis Brevis(APB)-abducts the thumb Flexor pollicis brevis(FPB)-flexes the thumb Adductor pollicis adducts the thumb APB, FPB and opponens pollicis are the 3 thenar muscles. Reference: Textbook of anatomy upper limb and thorax, Vishram Singh,2nd edition, page no.144 Figure 11.2,page no:145- Textbook of anatomy- upper limb & thorax - vishram singh', 'role': 'assistant'}]