This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mechanical injuries, Subject name: Forensic Medicine
[{'content': 'Feature that differentiates true from aificial bruise \nSelect and explain. \nA. Round shape, irregular margins, B. Irregular shape with regular margins, C. Swelling of surrounding area, D. Erythema of surrounding areas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: contusion: not well defined, diffuse, and irregular margins Aificial bruise: well defined with regular margins. Ref: FORENSIC MEDICINE AND TOXICOLOGY DR PC IGNATIUS THIRD EDITION PAGE 120', 'role': 'assistant'}]