This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Eye, Nose and Ear, Subject name: Anatomy
The arrow marked structure is ? 
Select and explain. 
A. Macula, B. Utricle, C. Saccule, D. Endolymphatic sac
D: Endolymphatic sac
Answer: D: Endolymphatic sac 
Explanation: - The diagram is showing inner ear & the arrow marked structure is endolymphatic sac .