This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
Positive urinary anion gap is found in- 
Select and explain. 
A. Alcholic ketoacidosis, B. Diabetic ketoacidosis, C. Renal tubular acidosis, D. Diarrhea
C: Renal tubular acidosis
Answer: C: Renal tubular acidosis 
Explanation: Urinary anion gap : used to differentiate GIT causes from Renal causes. UAG= Urine anions - urine cations =( HCO3-) - (NH4+) NORMAL = 0 In GIT cause : NEGATIVE In Renal cause : POSITIVE Ref: Harrison&;s 19thE