This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
[{'content': 'What laboratory evaluation is most likely to be abnormal in this 10-year-old patient who also had discrete facial erythema? \nSelect and explain. \nA. CD4 count, B. Creatine kinase, C. Rheumatoid factor, D. Thyrotropin', 'role': 'user'}, {'content': "Answer: B \nExplanation: Answer B. Creatine kinaseMultiple hyperkeratotic, erythematous, flat papules with central atrophy are notable on the dorsum of the metacarpophalangeal and interphalangeal joints, consistent with Gottron's papules. Though muscle-strength examination was normal, laboratory evaluation revealed an elevated level of creatine kinase suggestive of dermatomyositis.", 'role': 'assistant'}]