This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anaesthesia, Subject name: Anaesthesia
Inducing agent with maximum incidence of vomiting 
Select and explain. 
A. Ketamine, B. Etomidate, C. Thiopentone, D. Propofol
B: Etomidate
Answer: B: Etomidate 
Explanation: Postoperative nausea and vomiting are more common following etomidate than following propofol or barbiturate induction. Propofol also possesses significant antiemetic activity with small (sub hypnotic) doses (i.e., 10 mg in adults). The median concentration of propofol with an antiemetic effect was 343 ng/mL, which also causes a mild sedative effect. This concentration can be achieved by an initial dose of propofol infusion of 10 to 20 mg followed by 10 ug/kg/minute. Ref: Miller's anesthesia 8th edition Ref: Morgan & Mikhail's clinical anesthesiology 6e