A class of 40 students completed a survey on what pets they like. The choices were: Cats, Dogs, and Birds. Everyone liked at least one pet. 10 students like Cats and Birds but not Dogs. 2 students liked Dogs and Birds but not Cats. 12 students liked Cats and Birds, while 8 students liked Cats and Dogs. All in all, 28 students liked Cats, 19 students liked Dogs and 15 students liked Birds. How many students only liked Cats? O 10 O 1 0 9 O 2