This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
Conjunctival mucosal overgrowth over cornea- 
Select and explain. 
A. Pterygium, B. Pingecula, C. Vernal keratoconjunctivitis, D. Herbe's pit
A: Pterygium
Answer: A: Pterygium 
Explanation: Pterygium is a degenerative conjunctival fold which encroaches on the cornea in the palpebral area. It must be differentiated from pseudopterygium (an inflammatory fold of conjunctiva encroaching on cornea).Pterygium (L. Pterygion = a wing) is a wing-shaped fold of conjunctiva encroaching upon the cornea from either side within the interpalpebral fissure ref: A K KHURANA OPHTALMOLOGY,E4, Page-80 ref img