we'll i'd predict like this ...
-merc has Monster, so coke won't go there
-Red BUll has ... well Red bull
-Ferrari has one of the energy drinks associated with it (can't remember it's name)
-Mclaren has Lucozade (GSK)
so if coke wanted a race winning team , the only choice was between WilliamsF1 and Lotus F1, and i think if they had made the decision right after bercelona GP, then williams would've gotten it, but seeing how there car failed to score as much as it should've , They probably chose LotusF1 (i think bernie played a big part in who got what) and not to mention kimi's comeback has created so much hype, it's no wonder Coke chose LotusF1.