What Method Is Used to Release the N-Linked Glycan Groups $\beta$

Multiple Choice

What method is used to release the N-linked glycan groups from the membrane-associated glycoconjugates shown in 1 in the figure below?

A) enzymatic cleavage using PNGaseF
B) chemical cleavage using a $\beta$ -elimination reaction
C) chemical cleavage using a Schiff base intermediate
D) enzymatic cleavage using $\beta$ -galactosidase