Help with exec command and file descriptors??

im having trouble with the comprehending the exec command and the use of file descriptors.
given:

#!/bin/sh

exec 4>&1
exec 1>&2
exec 2>&4
exec 4>&-

echo Hello

would the standard output of this script be sent to STDOUT, STDERR or neither and why???

thanks for the help.

Please stop posting homework/classwork questions.