This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carcinoma Ovary, Subject name: Gynaecology & Obstetrics
[{'content': 'Oligohydroamnios is AFI- \nSelect and explain. \nA. <8cm, B. <5cm, C. <2 cm, D. <1 cm', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., < 5 cm Oligohydramnios1) AFI <5 cm or single largest vertical pocket < 2cm2) Amniotic fluid less than 100 mLEtiologyChromosomal AbnormalitiesUteroplacental Insufficiency* Congenital anomalies (e.g., renal agenesis and posterior urethral valves)* IUGR* Postdatism/postterm pregnancy* PROM* Twin-to-twin transfusion* Hypertension* Preeclampsia* NSAIDs, angiotensin-converting enzyme inhibitors* Idiopathic", 'role': 'assistant'}]