This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ballistics, Subject name: Forensic Medicine
[{'content': 'Abrasion collar is seen in: \nSelect and explain. \nA. Gunshot injury, B. Stab wound, C. Drowning, D. Railway track accident', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Abrasion collar/ring: Proof of bullet entry wound. Due to spinning motion of bullet. Impoance: Round Abrasion collar - if the bullet hits at right angle to the skin surface. Oval abrasion collar - if the bullet hits at oblique angle to the skin surface Diameter of the entry wound + abrasion collar gives the approximate diameter of the bullet. Grease collar (bullet wipe): A black/gray colored ring is seen lining the entrance wound. Due to the deposition of lubricants, gun oil or lead from the bullet.', 'role': 'assistant'}]