Which Linux command changes file permissions using numeric notation?

Correct answer: chmod

Option B is correct because the chmod command is used on Linux and Unix systems to change file permission bits using either symbolic notation or numeric (octal) notation, such as 755 or 644. Option A is incorrect because chown changes the ownership of a file or directory, specifically its user and group owner, not its permission bits. Option C is wrong because chgrp changes only the group ownership of a file, not its read, write, or execute permissions. Option D is incorrect because setfacl manages Access Control Lists, which extend standard permissions with finer-grained per-user and per-group entries; it is not the command for standard numeric permission changes.