Answer:
The correct answer is A: TAB.
The TAB key is used to set the position where the next character will be shown on the screen or printed on paper. When the TAB key is pressed, the cursor moves to the next tab stop, which is a predefined position.
Here is a detailed explanation:
1. TAB:
- The TAB key is a key on the keyboard that is used to create horizontal space.
- It is commonly used in word processing programs and text editors to align text or create columns.
- When the TAB key is pressed, the cursor moves to the next tab stop.

2. Tab Stop:
- A tab stop is a predefined position on the screen or paper where the cursor stops when the TAB key is pressed.
- By default, tab stops are set at regular intervals, usually every 8 characters.
- Tab stops can be modified to align text or create custom spacing.

3. Usage:
- Pressing the TAB key multiple times moves the cursor to the next tab stop.
- It is commonly used to align text in tables or create indentation in documents.
- In programming languages, the TAB key is often used to format code for readability.

4. Other options:
- B: INPUT: The INPUT command is used to get user input in programming languages.
- C: WRITE: The WRITE command is used to write data to a file or output device.
- D: PRINT: The PRINT command is used to display output on the screen or paper.

In conclusion, the TAB key sets the position where the next character will be shown on the screen or printed on paper. It is a useful tool for aligning text and creating spacing in documents.