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: Pediatrics
A 12 year old boy had severe vomiting and diarrhoea. He was brought to the hospital bacause of severe oliguria. He was given IV fluids and furosemide without any diuresis. Blood beichemistry revealed : Urea 120 mg% and serum creatinine 4 mg%. The most likely diagnosis is - 
Select and explain. 
A. Preneal azotemia, B. Haemolytic uraemic syndrome, C. Acute glomerulonephritis, D. Acute tubular necrosis
B: Haemolytic uraemic syndrome
Answer: B: Haemolytic uraemic syndrome 
Explanation: Ans. is 'b' i.e., Hemolytic uremic syndrome