Final answer:
The correct method to access the BIOS setup program is to press a key during the BIOS POST, usually indicated on the screen shortly after the computer is turned on.
Step-by-step explanation:
The method for accessing the BIOS setup program is B. press a key during the BIOS POST. POST stands for Power-On Self-Test, and it's the initial set of diagnostic tests performed by the computer right after it's powered on. During POST, the screen usually displays a message such as 'Press F2 to enter Setup' or 'Press DEL to enter setup,' which indicates which key needs to be pressed to enter the BIOS setup utility. The specific key can vary depending on the motherboard manufacturer. It is important to press this key at the right time, which is usually within a few seconds after the computer starts up.
Options A, C, and D are not standard methods for accessing BIOS setup. Accessing BIOS setup through the Control Panel in Windows or using a motherboard jumper are not common practices, and booting from a BIOS setup floppy disk is obsolete.