Final answer:
The file system used on hard disks in Windows is the NTFS file system.
Step-by-step explanation:
The correct answer is a) True. The file system used on hard disks in Windows is indeed the NTFS file system. NTFS stands for New Technology File System and it is the default file system used by modern versions of Windows, including Windows 10. NTFS provides several advantages over the older FAT file system, such as improved security, support for larger file sizes, and better file organization.