Glycoside linkage is the ether bond present in between two :

The correct answer is Option (4) → Monosaccharides

In disaccharides and polysaccharides, monosaccharide units are joined through an oxygen atom: the hemiacetal −OH of one sugar (e.g. at C-1 of glucose) combines with an −OH of the next sugar and a molecule of water is lost. This C–O–C (ether-type) link between two monosaccharide units is the glycosidic linkage.

    \( \displaystyle \ce{C6H12O6 + C6H12O6 -> C12H22O11 + H2O} \)

For example, sucrose is α-D-glucose and β-D-fructose joined between C-1 of glucose and C-2 of fructose; maltose is two α-D-glucose units joined between C-1 and C-4.

Why the other options are incorrect

• Option (1) Amino acids — Incorrect. Amino acids are joined by the peptide linkage (−CO−NH−), an amide bond, not an ether bond.

• Option (2) Nucleic acids — Incorrect. Within a nucleic acid the nucleotides are joined by phosphodiester linkages between the 5′ and 3′ carbons of the sugar units.

• Option (3) Vitamins — Incorrect. Vitamins are separate small organic molecules of varied structure; they are not linked to one another by glycosidic bonds.

NCERT (2026-27 edition):
Disaccharides – “You have already read that disaccharides on hydrolysis with dilute acids or enzymes yield two molecules of either the same or different monosaccharides. The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Such a linkage between two monosaccharide units through oxygen atom is called glycosidic linkage.”