This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Uveal tract, Subject name: Ophthalmology
[{'content': 'Chorioretinitis is caused by - \nSelect and explain. \nA. Toxoplasmosis, B. CMV, C. Rubella, D. Oncocerca volvulus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Toxoplasmosis is known to produce necrotising chorioretinitis. Systemic toxoplasmosis occurs in humans in two forms: congenital and acquired. 1. Congenital toxoplasmosis:The characteristic triad of congenital toxoplasmosis includes: convulsions, chorio-retinitis and intracranial calcification. 2. Acquired toxoplasmosis:Most of the patients are subclinical (asymptomatic); and the typical chorioretinal lesion similar to congenital toxoplasmosis is discovered by chance.', 'role': 'assistant'}]