What is the minimum HDD requirement for Windows 10?

The minimum HDD requirement for Windows 10 indicates the necessary disk space to install the operating system effectively. For a 32-bit version, a minimum of 16GB is essential, while the 64-bit version requires at least 20GB. This is because the operating system must store not only the core files but also system updates, user settings, and applications, which all consume space on the hard drive.

Understanding the requirements for different versions helps in system compatibility and ensures that users have enough space to operate the OS efficiently. The other choices either underestimate the space needed or don't align with Microsoft's guidelines for system requirements, making them unsuitable options.