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 for cosmetic concern. Treatment should be - 
Select and explain. 
A. Surgical excision, B. Left alone, C. Antihistaminics, D. Antibiotics
B: Left alone
Answer: B: Left alone 
Explanation: Asymptomatic pterygium which is not a progressive is best left alone. Reference : Parson 22nd edition page 181,182;