Which option is used when running smbclient with a file containing user credentials?

The `-F` option for `smbclient` is not a valid or standard option for specifying a credentials file.

The `-c` option for `smbclient` is used to execute a command string, not to specify a credentials file.

The `-s` option for `smbclient` is used to specify a service (share) to connect to, not a credentials file.

The `smbclient` command uses the `-a` option (or `--authentication-file`) to read authentication credentials, such as username and password, from a specified file rather than prompting the user or using other methods.