Final answer:
The ls command option to view file inode numbers is -i, which is not listed among the given choices. Combining -i with -l (ls -il) will show inode numbers with detailed file information. Options -l, -o, -a do not specifically mention inodes, but -l provides the most detailed information which could be considered the closest match.
Step-by-step explanation:
The option of the ls command used to view the file inode number is -i. However, this option is not listed among the choices provided. If you need to see the inode numbers along with the long listing format which includes permissions, owner, group, size, and modification date you would combine -i with -l (i.e., ls -il). The options given in the question do not directly answer the query: -l provides a long listing format, -o provides the long listing format minus the group information, -a shows all files including hidden files, but none of these specifically mention inodes. If constrained by the options given and focusing on the ones closest to showing inodes, -l would be the closest match as it's part of a detailed list, but it does not show inodes on its own.