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
Anteroposterior diameter of normal adult eyeball is: 
Select and explain. 
A. 25 mm, B. 24 mm, C. 23.5 mm, D. 23 mm
B: 24 mm
Answer: B: 24 mm 
Explanation: Ans. 24 mm