This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Symptomatic Conditions, Subject name: Ophthalmology
[{'content': 'Most common foreign body to cause penetrating injury to ciliary body \nSelect and explain. \nA. Ball, B. Hammer and chisel, C. Gun bullet, D. Vegetative material', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Hammer and chisel Ref: A.K. Khurana 6th ed. /163, 437', 'role': 'assistant'}]