Which among the following types of linkages is present in cellulose?

• A
  $1 \rightarrow 6$ $\beta$-glycosidic linkages
• B
  $1 \rightarrow 4$ $\beta$-glycosidic linkages
• C
  $1 \rightarrow 4$ $\alpha$-glycosidic linkages
• D
  $1 \rightarrow 6$ $\alpha$-glycosidic linkages