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: Pharmacology
Despite their sho half-lives (2 hours), Proton pump Inhibitors (PPIs) cause a prolonged suppression of acid secretion (up to 48 hours) because: 
Select and explain. 
A. They are prodrugs and undergo activation gradually, B. They exit from the plasma and enter acid secretory canaliculi and stay there, blocking the secretion of acid for a long time, C. They irreversibly inhibit the proton pump molecule and hence, acid secretion requires synthesis of new proton pumps, D. They are available as enteric coated capsules, from which drug is gradually released
C: They irreversibly inhibit the proton pump molecule and hence, acid secretion requires synthesis of new proton pumps
Answer: C: They irreversibly inhibit the proton pump molecule and hence, acid secretion requires synthesis of new proton pumps 
Explanation: Ans. c. They irreversibly inhibit the proton pump molecule and hence, acid secretion requires synthesis of new proton pumps Inhibition of acid secretion is also more prolonged because of the irreversible inhibition of the enzyme caused by the covalent bond to the proton pump.