The DOS command "DISK COPY" is used to send the contents of one disk to another, making it an output operation.

Command: DISK COPY

The correct answer for the given question is option 'B' - DISK COPY. The DISK COPY command is used in MS-DOS to send the contents of the screen to an output device.

The DISK COPY command is used to make a duplicate copy of a floppy disk. When executed, it prompts the user to insert the source disk and the destination disk. After both disks are inserted, the command copies the entire contents of the source disk to the destination disk. During this process, the progress of the copying operation is displayed on the screen.

Explanation:

To understand why the DISK COPY command is the correct answer, let's take a look at the other options:

a) BREAK: The BREAK command is used to enable or disable the extended Ctrl+C checking feature. It is not related to sending the contents of the screen to an output device.

c) MORE: The MORE command is used to display the output of a command one screen at a time. It is used when the output of a command is too long to fit on a single screen. While the MORE command allows the contents of the screen to be viewed in a controlled manner, it does not send the contents to an output device.

d) ASSIGN: The ASSIGN command is used to assign a drive letter to a specific physical or logical drive. It is used to make a drive letter assignment permanent. It does not send the contents of the screen to an output device.

In conclusion, the DISK COPY command is the correct option because it is specifically designed to copy the contents of a disk and display the progress on the screen. This process involves sending the contents of the screen to an output device, making it the appropriate command for the given question.