This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Cholinergic, Subject name: Pharmacology
Mechanism of action of Oxybutynin? 
Select and explain. 
A. Cholinergic, B. Anticholinergic, C. Adrenergic, D. Selectively inhibits M2 receptor
B: Anticholinergic
Answer: B: Anticholinergic 
Explanation: Ans. (b) AnticholinergicRef. KDT 6th ed. /107; Katzung Pharma 10th ed. Ch 8 MOA oxybutynin - cholinergic-muscarinic receptor antagonist* Oxybutynin is a selective M3 receptor blocker, used to relieve bladder spasm after urologic surgery, eg, prostatectomy. It is also used to relieve urinary and bladder difficulties, including frequent urination and inability to control urination, by decreasing muscle spasms of the bladder.* It competitively antagonizes the M3 subtypes of the muscarinic acetylcholine receptor.* M3 receptor blockers: (Mn: SOFT blaDar)# Solifenacin, Oxybutynin, Flavoxate, Tolterodine and Darifenacin