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
A patient presented with unilateral proptosis which was compressible and increases on bending forward. No thrill or bruit was present. MRI shows a retro orbital mass with enhancement. The likely diagnosis is - 
Select and explain. 
A. AV malformations, B. Orbital encephalocoele, C. Orbital varix, D. Neurofibromatosis
C: Orbital varix
Answer: C: Orbital varix 
Explanation: Proptosis on bending forward is typical of intermittent proptosis. Orbital varices constitute about 90% of cases of intermittent proptosis). So, it is seen in venous malformation, i.e., orbital varixes (not AV malformation).
AV malformation (carotid - cavernous fistula) and encephalocele cause pulsatile exophthalmos.