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
Smallest diameter of the eyeball is: 
Select and explain. 
A. Veical, B. Horizontal, C. Anteroposterior, D. More than 24 mm
A: Veical
Answer: A: Veical 
Explanation: Ans. Veical