5.1) The following 1s command displays the two files under directory /etc. $ ls -l -X-r /etc tail -2 drwxr-xr-x 2 root root 4096 2020-11-18 Packagekit drwxr-xr-x 3 root root 4096 2020-07-31 NetworkManager $ Based on what is presented above, please fill the blanks below (2 points each, total 10 points): 5.1a) option causes ls to print files in a long listing Option -l is used for format 5.1b) Option -X is used for sort by extension name 5.1c) Option -r is used for 5.1d) Symbol "I" is used for 5.1e) Command "tail -2" is used for