Can I report the same study twice but with different authors?
There is a general prohibition on publishing the same work twice, whether with different co-authors or not.
One option is just to add both of them on same paper.  Put yourself as first author.  After that, it's other people riding the sled.  Most people understand the main contribution is first author.
Potentially there is some way to carve the study into different pieces and do different papers with each person without violating (1).  Or maybe give one of them some later co-authorship (say on a review or followup study).  I wouldn't go through too many contortions though just for the purpose of doing separate co-authorships.  Divide your overall work as you think it makes most sense to the reader and most benefit to you.  Then figure out what coauthors are deserved where.
Also consider to use the "acknowledgements section" if a contribution was made but you do not think it rises to coauthorship.
Finally, I would make sure that A knows about what B is asking for.  They may be buddies/colluders or rivals or whatever. But he can advise you. I bet he says go with (2).