You opened a batch file in Notepad and are observing the following lines. (The line numbers are for reference only.)
1- ECHO This batch file deletes the temp files
2- DEL %TEMP Q
3- REM The temp files were deleted
4- PAUSE Which of the lines is a comment?

3- REM The temp files were deleted

Explanation:

REM is a keyword that must be followed by a space or tab character, then the comment. During execution of the script, everything on the line following the REM will be ignored, including quotes, redirection symbols, and other commands.

Line 1 will display some information to the user

Line 2 deletes temporary files

Line 3 is the comment as it is not executed.

Line 4 is to pause execution.

answerdmz;