The structures marked with arrows in the photo below are ________ and are used to ________.

A) polyhydroxyalkanoates; sequester reactions using bicarbonate or carbon dioxide and Rubisco
B) polyhydroxyalkanoates; store carbon for energy
C) carboxysomes; store carbon for energy
D) carboxysomes; sequester reactions using bicarbonate or carbon dioxide and Rubisco
E) heterocysts; sequester reactions using bicarbonate or carbon dioxide and Rubisco