If we include marine carnivores, many species of seal would predominate. #3 and #4 would be the crabeater seal with 11 million and harp seal with 8 million.
Maybe the taxonomy is changed, but I have doubts about the correctness of the source information behind this quiz. I take "carnivore" to mean a mammal in Order Carnivora. Surely there are more coyotes than brown bears. Same goes for various sorts of mustelids, all of which are in Order. Carnivora. Weasels, skunks, mongooses--they'd all outnumber their larger relatives by a large margin. Raccoons are an obvious miss here, too. Same goes for various civets and martens.