This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Fastest acting receptor/transduction mechanism is 
Select and explain. 
A. Adenylyl cyclase-cyclic AMP pathway, B. Phospholipase C-IP3:DAG pathway, C. Intrinsic ion channel operation, D. Nuclear receptor
C: Intrinsic ion channel operation
Answer: C: Intrinsic ion channel operation 
Explanation: Ref-KDT 6/e p40 Drugs acting and ionotropic receptor are fast acting where as those acting through nuclear receptors are slowest in action