This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: DNB 2018, Subject name: Pharmacology
Tolterodine used in overactive bladder acts by blocking which of the following receptors? 
Select and explain. 
A. M1, B. M2, C. M3, D. M4
C: M3
Answer: C: M3 
Explanation: Selective M3 antagonists acting on GIT and bladder Selective M3 antagonists acting only on bladder (vesicoselective) Derifenacin Oxybutynin Solifenacin Flavoxate Tolterodine Trospium chloride