This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Inverse agonist is - 
Select and explain. 
A. Buspirone, B. b-carboline, C. Flumazenil, D. Zolpidem
B: b-carboline
Answer: B: b-carboline 
Explanation: Ans. is 'b' i.e., b-carboline Drugs acting at BZD site of GABAA receptors o Agonist at BZD site of GABAA receptor -4 Benzodiazepine, Zolpidem, Zopiclone, Zoleplon. o Inverse agonist at BZD site of GABAA receptor --> b-carboline o Competitive antagonist at BZD site of GABAA receptor ---> Flumazenil