This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pharmacology
Which of the following is a carbonic anhydrase inhibitor? 
Select and explain. 
A. Acetazolamide, B. Hydrochlorothiazide, C. Furosemide, D. Mannitol
A: Acetazolamide
Answer: A: Acetazolamide 
Explanation: Carbonic anhydrase is an enzyme which catalyses the reversible reaction H2O + CO2 - H2C03 Hence, Carbonic anhydrase functions in CO2 and HC03 transpo and in H+ ion secretion. Carbonic anhydrase inhibitors act by non-competitive but reversible inhibition of this enzyme. eg- tazolamide, dorzolamide and brinzolamide. Hydrochlorothiazide-Inhibits Na-Cl- sympoer acts on distal tubule Furosemide-loop diuretic acting on NA+-K+-2CL PUMP Mannitol-OSMOTIC diuretic