This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Investigation in ophthalmology and miscellaneous topics, Subject name: Ophthalmology
This is used in diagnosis of: 
Select and explain. 
A. Steropsis, B. Colour vision, C. Refractive error, D. Strabismus
A: Steropsis
Answer: A: Steropsis 
Explanation: The above image shows Titmus fly test used for diagnosis of stereopsis.