What are my options for venting a bathroom exhaust fan?
The "best" approach is to take the shortest straight path to get the exhaust air out of your house.  Generally that's via a roof vent.  Check out this answer for a little more info.

Your plan A, two bends and out the gable end is fine as an alternative.  10 feet is not a very long way for a bathroom exhaust vent.  If possible, use a rigid vent to avoid sagging and possible condensation build-up.