This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skin lesions, Subject name: Dental
[{'content': 'Linear discontinuation of skin is known as: \nSelect and explain. \nA. Ulcer, B. Excoriation, C. Erosion, D. Fissure', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fissure is a linear crack/discontinuation of skin. Both erosions and ulcers are raw lesions. Erosion is due to loss of only epidermis, while ulcer is due to loss of both epidermis and dermis. Excoriations, also known as scratch marks, occur due to itching or scratching, which erode the epidermis or upper dermis.', 'role': 'assistant'}]