This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
Phase 4 clinical trial also called as 
Select and explain. 
A. Therapeutic confirmation, B. Post marketing surveillance, C. Therapeutic exploration and dose ranging, D. Human pharmacology and safety
B: Post marketing surveillance
Answer: B: Post marketing surveillance 
Explanation: Phase IV: Postmarketing surveillance/ studies After the drug has been marketed for general use, practicing physicians are identified through whom data are collected on a structured proforma about the efficacy, acceptability and adverse effects of the drug. Uncommon/idiosyncratic adverse effects, or those that occur only after long-term use and unsuspected drug interactions are detected at this stage. Ref:- kd tripathi; pg num:-80