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: Pharmacology
Which of the following anti - glaucoma drug can likely cause black pigmentation on conjunctiva 
Select and explain. 
A. Adrenaline, B. Latanoprost, C. Beta blockers, D. Pilocarpine
A: Adrenaline
Answer: A: Adrenaline 
Explanation: Adrenaline used in glaucoma can lead to conjunctival pigmentation because of adrenochrome.