The correct command to copy the contents of the directory /etc/, including all sub-directories, to /root/ is cp -r /etc/* /root. This command uses the cp command, which stands for copy, and is used to copy files and directories on Linux and Unix systems. The command also uses the following options and arguments123:
The -r option, which stands for recursive, and tells cp to copy all files and sub-directories of the source directory. Alternatively, the -R option can be used, which has the same effect as -r.
The /etc/* argument, which specifies the source directory and all its contents. The asterisk (*) is a wildcard character that matches any file or directory name. This argument tells cp to copy everything inside the /etc/ directory, but not the directory itself.
The /root argument, which specifies the destination directory. This argument tells cp to copy the source files and sub-directories to the /root/ directory.
The other options are incorrect because they use different commands or syntax that do not copy the contents of the directory /etc/, including all sub-directories, to /root/. For example:
Option A uses the copy command, which is not a valid Linux command. The correct command is cp.
Option C uses the -v option, which stands for verbose, and tells cp to print verbose output. This option does not affect the copying process, but only the output. It also does not include the -r or -R option, which is necessary to copy the sub-directories.
Option D uses the rcp command, which stands for remote copy, and is used to copy files between different hosts on a network. This command is not relevant for copying files on the same host.
Option E uses the -R option, which is correct, but also uses the . argument, which is incorrect. The dot (.) is a special character that matches any single character. This argument tells cp to copy only the files and directories that have a dot in their name, which may exclude some files and directories that do not have a dot.
References: 1: Cp Command in Linux (Copy Files) | Linuxize 2: cp command in Linux with examples - GeeksforGeeks 3: How to Copy Files and Directories in the Linux Terminal
