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': "Rider's bones are ossification of \nSelect and explain. \nA. Adductor brevis, B. Adductor longus, C. Adductor magnus, D. Flexor digitorum superficialis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Rider's bone develops in the tendon of adductor longus in professional riders. It is a sesamoid bone.that has no periosteum and ossifies after bih. Reference: BD Chaurasia's handbook of general anatomy, 5th edition, pg 55", 'role': 'assistant'}]