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
Weight of an adult eyeball is: 
Select and explain. 
A. 7 g, B. 9 g, C. 11 g, D. 13 g
A: 7 g
Answer: A: 7 g 
Explanation: Ans. 7 g