Which one of the following reactions is not explained by the open chain Structure of glucose

Which one of the following reactions is not explained by the open chain Structure of glucose:

(a) Formation of pentaacetate of glucose with acetic anhydride.
(b) formation of addition product with 2,4 DNP reagent
(c) Silver mirror formation with Tollen’s reagent
(d) existence of alpha and beta forms of glucose.

Option D is the Correct answer. Explanation: Existence of alpha and beta forms of glucose is the reactions that is not explained by the open chain Structure of glucose.