In compliance with the FHS, in which of the directories are man pages found?

The FHS defines /usr/share as the location for architecture-independent read-only data shared across a system, and explicitly requires manual pages to be stored in /usr/share/man. This path is the standard location recognized by the 'man' command on compliant Linux distributions. Non-compliant paths such as /usr/man are considered legacy and were superseded by this standard.

/opt is reserved by the FHS for optional third-party add-on software packages and is not the location for system man pages.

/usr/doc is a legacy path that predates the FHS; the standard requires /usr/share/doc for documentation and /usr/share/man for man pages.

/var/pkg/man is not a path defined or recognized anywhere in the FHS.

/var is designated by the FHS for variable data such as logs and spool files, not for static documentation like man pages.