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
A 20 years female is diagnosed to have pterygium. She does not have any clinical symptoms except lor cosmetic concern. Treatment should be - 
Select and explain. 
A. Surgical excision, B. Left alone, C. Antlhislaminlcs, D. Antibiotics
B: Left alone
Answer: B: Left alone 
Explanation: Pterygium is an asymptomatic condition in the early stages, except for cosmetic intolerance. Surgical excision is the only satisfactory treatment, which may be indicated for: (1) cosmetic reasons, (2) continued progression threatening to encroach onto the pupillary area (once the pterygium has encroached pupillary area, wait till it crosses on the other side), (3) diplopia due to interference in ocular movements. ref: A K KHURANA OPHTALMOLOGY,E4, Page-81