This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Skin
[{'content': 'Microdermasion is done with: \nSelect and explain. \nA. Aluminium oxide crystals, B. Aluminium trihydrate crystals, C. Ferrous oxide crystals, D. Ferric oxide crystals', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Microdermabrasion is resurfacing technique with superficial skin wound achieved with aluminium oxide crystals. Ref: Textbook of dermatosurgery & cosmetology, Satish S savant, E-2, P-620.', 'role': 'assistant'}]