Originally Posted by
noreservations
Does that mean C is full and won't open up?
At the top of the EF results page for American it says
Zero value award classes may not always be shown. Click here for more information
and following the link for more information gets you
Sometimes American will return just two flights where the requested award seat availability is zero on both flights, even when there are later non-stop/direct flights scheduled. This is American's way of indicating that none of the later flights have available inventory for the request class either.
So C may well show up again, but it is currently 0 for all these other flights.