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
Fontana-Masson stain mainly stains   what granules  in the  cytoplasm 
Select and explain. 
A. Melanin, B. Copper, C. Ferritin, D. Hemoglobin
A: Melanin
Answer: A: Melanin 
Explanation: Fontana masson  stains  mainly used to detect melanin granules in cytoplasm of tumour cells  of melanoma.