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: Ophthalmology
The most common cause of bilateral proptosis in children is: 
Select and explain. 
A. Cavernous hemangioma, B. Fibrous Histiocytoma, C. Chloroma, D. Rhabdomyosarcoma
C: Chloroma
Answer: C: Chloroma 
Explanation: The most common cause of bilateral proptosis in children is not definitively established, but metastatic neuroblastoma and/or leukemia should be considered. Common causes of bilateral proptosis in children are congenital skeletal deformities followed by lymphoma, leukemia and other lymphoproliferative disorders. Chloroma is a solid tumor consisting of myeloid leukemic blasts. Of all the options given it is the best answer. Ref: The Massachusetts Eye and Ear Infirmary review manual for Ophthalmology - Page 186; Surgical Atlas of Orbital Diseases - Page 52.