The correct answer is C. cmp.
The command cmp is used to compare two files. It prints a message indicating whether the files are identical, the first file is newer than the second file, or the second file is newer than the first file.
The command ccp is used to copy files. It copies the source file to the destination file.
The command du is used to report the disk usage of a file or directory.
The command comp is not a valid command.
Here is an example of how to use the cmp command:
cmp file1 file2
If the files are identical, the command will print nothing. If the first file is newer than the second file, the command will print file1 is newer than file2. If the second file is newer than the first file, the command will print file2 is newer than file1.