This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
A chest physician performs bronchoscopy in the procedure room of the outpatient depament. To make the instrument safe for use in the next patient waiting outside, the most appropriate method of disinfection is by: 
Select and explain. 
A. 70% alcohol for 5 min, B. 2% glutaraldehyde for 20 min, C. 2% formaldehyde for 10 min, D. 1% sodium hypochlorite for 15 min
B: 2% glutaraldehyde for 20 min
Answer: B: 2% glutaraldehyde for 20 min 
Explanation: Techniques for Sterilization Steam Surgical instruments Ethylene Oxide Hea lung machine, respirators , dental labs Hot air oven Glass syringe, test tubes, flasks, cutting instruments Irradiation (gamma rays) Industrial packing Paraacetic acid (STERIS) Flexible endoscopes Isopropyl alcohol Clinical thermometer Beta propiolactone > Formaldehyde Fumigation of OT, labs, wards 2% Glutaraldehyde Endoscope (Cystoscope, Bronchoscope) Autoclaving Culture media, suture materials except catgut Ref: Bailey 24th edition Pgno: 135