What Bond Is Responsible for the Branch Points in Glycogen $\alpha$

What bond is responsible for the branch points in glycogen and amylopectin?

A) $\alpha$ (1->4) glycosidic linkages
B) $\beta$ (1->4) glycosidic linkages
C) $\alpha$ (1->6) glycosidic linkages
D) $\beta$ (1->6) glycosidic linkages
E) 3'-5' phosphodiester linkages