Smoke detector placement in long open concept space
I would place it halfway between B and C as well
I would place the smoke alarm halfway between B and C, or in other words, about in the middle of the living/dining space.  If we look at the NFPA 72 prescriptive criteria for smoke alarm/detector siting, we first note that we can't place the alarm within 10' of the range (29.8.3.4 point 4), which means that A is right out.  This is indeed for the reason you state: a smoke alarm in a kitchen would have far too many nuisance alarms to be useful, even though modern alarms are better at rejecting nuisance smoke than older units thanks to enhanced UL testing.
Likewise, B would be a bit nuisance-alarm-prone as well, as it's within the 20' radius that requires enhanced nuisance smoke rejection, while C is out of range of the back of the dining area. (No point in the room can be over 21' away from a typical smoke alarm as per the 17.3.2.3.1 point 2 prescriptive criteria.)  As a result, roughly midway through the living/dining area is probably going to be the best place for the smoke alarm to go.