I voted other just because of the "two food group" thing. I know you said it's required, but I guess I feel a snack of "just" apples or "just" crackers would be fine for a 2.5 hour session.
There are guidelines for our play school but alternate snacks are kept in the classroom in case a snack doesn't "work" for all the kiddos. Right now dd1 is in a group of 8 kiddos and in that group there is a total dairy allergy (total...no whey, casein, etc), a little one with a gluten free diet, another who is just wheat-free, two vegans, a chocolate allergy, a peanut allergy, a tree nut allergy, a strawberry allergy, and a soy allergy. So finding a single snack can be hard...I think given the guidelines it would be nearly impossible to find a snack that covered two food groups and still appealed to a group of 2 year olds.
Right now they have a lot of apple juice, apple slices, corn cakes, and rice crackers.