The Layers in a Particular Gumball Are (1)an Outer Layer

The layers in a particular gumball are (1) an outer layer of citric acid and malonic acid; (2) a layer of sugar and flavoring; (3) a layer of sodium bicarbonate (NaHCO₃) ; and (4) gum.When a person starts to eat one of these gumballs,s/he puckers,smiles,and then foams at the mouth before starting to chew the gum itself.Where did the foam come from?

A) The sodium bicarbonate reacts with sugar,making carbon dioxide gas.
B) The sodium bicarbonate explodes when exposed to moisture.
C) The acids react with the sodium bicarbonate,making unstable carbonic acid.
D) The flavoring contains a foaming agent.
E) The acids react with the sugar making carbon volcano.