Which button should you press to enter the RBSU during POST? 05/21/2017 – by Mod_GuideK 0 Which button should you press to enter the RBSU during POST? A. F8 B. F9 C. F11 D. F12 SHOW ANSWERSCorrect Answer: B Explanation/Reference: References: Download Printable PDF. VALID exam to help you PASS.