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
In herpes zoster opthalmicus least involved nerve is? 
Select and explain. 
A. Facial, B. Infraorbital, C. Lacrimal, D. Nasociliary
A: Facial
Answer: A: Facial 
Explanation: Facial REF: khurana 4th ed p. 126-127 Herpes zoster virus lies dormant in the gasserian ganglion of trigeminal nerve to appear later, paicularly in elderly people with depressed cellular immunity in distribution of trigeminal nerve Here all except facial nerve is branches of trigeminal nerve hence is the answer.