This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Pharmacology
Which enzyme is inhibited by caffeine? 
Select and explain. 
A. Monoamine oxidase, B. Alcohol dehydrogenase, C. Phosphodiesterase, D. Cytochromo P 450
C: Phosphodiesterase
Answer: C: Phosphodiesterase 
Explanation: Aminophyllines(theophylline, caffeine) inhibits the release of ca from sarcoplasmic reticulum and inhibition of phosphodiesterase3/4 causes increased CAMP and bronchodilation ESSENTIALS OF MEDICAL PHARMACOLOGY SEVENTH EDITION KD TRIPATHI PG NO .225,227