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
If blood gas analysis reveal pH = 7.52, pCO = 30 ; pO2 = 105. This will be compensated by ? 
Select and explain. 
A. Compensatory respiratory acidosis, B. Compensatory respiratory alkalosis, C. Compensatory metabolic acidosis, D. Compensatory metabolic alkalosis
C: Compensatory metabolic acidosis
Answer: C: Compensatory metabolic acidosis 
Explanation: First step

Determine whether it is acidosis or alkalosis
Increase in pH suggests alkalosis
Second step
Look at CO2 or HCO3- to determine the cause
Decreased PCO2 suggests respiratory alkalosis
Respiratory alkalosis
Respiratory alkalosis occurs because CO2 is blown off in excess equation shifts to left and H+ conc. decrease which leads to alkalosis.
Now the kidneys compensate for this alkalosis by excreting more HCOO3-. This shifts the equation to right thus H+ conc. decreases.