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: Pathology
A 3 year old female child presented with skin papules. Which of the following is a marker of Langerhan's cell histiocytosis? 
Select and explain. 
A. CD 1a, B. CD 3, C. CD 68, D. CD 57
A: CD 1a
Answer: A: CD 1a 
Explanation: . CD 1a