COMPTIA A+ Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The primary job of the Master Boot Record (MBR) is to check the partition table for a partition that contains a valid operating system. When a computer is powered on, the BIOS looks for the MBR on the storage device to determine how to boot the operating system. The MBR includes information about the disk's partitions and the bootloader, which is crucial for initiating the operating system loading process. This function is essential for the proper startup of a computer, as it allows the system to locate the necessary files to load the operating system into memory.

The other functions mentioned in the options do not pertain to the primary responsibilities of the MBR. Allocating memory is managed by the operating system, the cooling system is handled by the hardware, and file storage management is also a function of the operating system. Thus, the role of the MBR is specifically centralized on the boot process and identifying valid partitions for operating system booting.