Which parameter should be set in smb.conf to enable off-line caching of data files.

`offline policy` is not a standard Samba `smb.conf` parameter for client-side caching.

`offline` is not a standard Samba `smb.conf` parameter for client-side caching.

The `csc policy` (Client Side Caching policy) parameter in `smb.conf` is used to control how Windows clients can cache files from the Samba share for offline access. Setting `csc policy = documents` allows clients to cache files for offline use and automatically synchronize changes, which is a common setting for user document shares.

`vfs objects = offline` would attempt to load a VFS module named "offline," which is not the correct parameter or value for controlling client-side caching. `vfs objects` specifies a stack of VFS modules.