User jack, whose account is configured to use the korn shell, logs in and examines...

He will get a "file not found" error, because the current directory is not in his seaech path.

He will get a "file not found" error, because his home directory is not in his search path.

The useradd script will execute, because jack is in the same directory that the script is located in.

The command /user/sbin/useradd will execute, because it is the last match in the search path.

The command /user/sbin/useradd will execute, because it is the first match in the search path.