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': 'Epiphora is: \nSelect and explain. \nA. Cerebrospinal fluid running from the nose after fracture of anterior cranial fossa, B. An epiphenomenon of a cerebral tumor, C. An abnormal overflow of tears due to obstruction of lacrimal duct, D. Eversion of lower eyelid following injury', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Epiphora is defined as watering from the eye due to physiological causes such as pump failure or mechanical obstruction in lacrimal passage. Ref: Textbook of Ophthalmology By Nema, 3rd Edition, Page 304', 'role': 'assistant'}]