Don't forget the explanation!
American medical assoc. indicates that X and "that" Y
We need "that" to make it clear that the medical association said two different things.
A and B are out.
this is misplaced "only" example
We want to stress that the efforts are not getting the success we want.
Thats why we need "only" and "partially successful" to be as close as
possible to each other
The best construct is " only partially successful"
C is best.