Explanation:

(A) A Boot Record:
Present. DOS floppy disks contain a boot sector (boot record) that helps in booting the system.

(B) A File Allocation Table (FAT):
Present. DOS uses FAT12 on floppy disks to manage files.

(C) A Root Directory:
Present. Floppy disks have a root directory to store information about files.

(D) BIOS:
Not present. BIOS (Basic Input/Output System) is firmware stored on the motherboard, not on the floppy disk.

Conclusion:

BIOS is not part of the floppy disk, so the correct answer is (D) BIOS.