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
[{'content': 'Corneal endothelium is embryologically derived from: \nSelect and explain. \nA. Neural crest, B. Ectoderm, C. Mesoderm, D. Endoderm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A. i.e. Neuroectoderm', 'role': 'assistant'}]