Lactose is a disaccharide involving a glycosidic linkage between

C-1 of $\mathrm{\beta }$-D-glucopyranose and C-2 of $\mathrm{\beta }$-D-galactopyranose

C-1 of $\mathrm{\alpha }$-D-glucopyranose and C-2 of $\mathrm{\beta }$-D-galactopyranose

C-1 of $\mathrm{\beta }$-D-glucopyranose and C-4 of $\mathrm{\beta }$-D-galactopyranose

C-1 of $\mathrm{\beta }$-D-galactopyranose and C-4 of $\mathrm{\beta }$-D-glucopyranose