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: Medicine
55 year old male patient who is a know case of chronic kidney disease present to emergency with vomiting and Is diagnosed with uremic acidosis. His ABG analysis report is
pH= 7.42
pCO2= 40
HCO3= 25
Na+= 140 mmol/L
K+= 3 mmol/L
Cl-= 95 mmol/L 
Select and explain. 
A. Respiratory acidosis, B. Respiratory Alkalosis, C. High Anion Gap metabolic acidosis + metabolic alkalosis, D. High Anion Gap metabolic acidosis + Respiratory Alkalosis
C: High Anion Gap metabolic acidosis + metabolic alkalosis
Answer: C: High Anion Gap metabolic acidosis + metabolic alkalosis 
Explanation: PH is higher, but CO2 and HCO3 look normal. So look at Anion gap = 20 .
But difference in HCO3 = 0  so is a case of High Anion Gap metabolic acidosis + metabolic alkalosis.