Explanation:

- Desktop Computers: These are standard computers typically used in one fixed location. They are designed for a wide range of tasks in homes and offices.

- Personal Computers and Tablet PCs: Personal computers include desktops and laptops meant for individual use. Tablet PCs are portable devices with touchscreens, providing computer-like functionality.

- Workstations: These are powerful computers designed for technical or scientific applications. They offer more performance than typical desktop computers.

- All of These: This option correctly includes all of the devices mentioned above. Each is a type of digital computer.

Correct Answer: Option 4 - All of these