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 intermittent exophthalmos is: 
Select and explain. 
A. Orbital varices, B. Cavernous haemangioma, C. Lymphangioma, D. Carotico-cavernous fistula
A: Orbital varices
Answer: A: Orbital varices 
Explanation: Ans. Orbital varices