This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
[{'content': 'This rash appeared 9 hours after a scuba dive. What is the diagnosis? \nSelect and explain. \nA. Decompression sickness, B. Jellyfish envenomation, C. Mycobacterium marinum infection, D. Phylum Porifera contact dermatitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer A. Decompression sicknessCutis marmorata is a dermal manifestation of decompression sickness. Initially, there is erythema accompanied by pruritus, and then the rash spreads irregularly and deepens in color. It develops a mottled appearance, with areas of pallor surrounded by cyanotic patches. During recompression, the rash resolves.', 'role': 'assistant'}]