This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Surgery
Oliguria is defined as:- 
Select and explain. 
A. Absence of urine production, B. More than 900 ml of urine excreted in a day, C. 600 ml to 700 ml of urine excreted in a day, D. Less than 300 ml of urine excreted in a day
D: Less than 300 ml of urine excreted in a day
Answer: D: Less than 300 ml of urine excreted in a day 
Explanation: Oliguria is defined as urine production less than 500 ml in a day