Glycosidic Bond Formation in Xylose

Steps:

• Identify xylose as an aldopentose with a free anomeric carbon (C1) in its ring form.
• Recognize glycosidic bond as a condensation reaction linking C1 of one xylose to a hydroxyl group (often C4) of another, releasing H2O.
• Examine diagrams for arrow or structure showing loss of water and ether linkage between rings.
• Select the option depicting two xylose rings connected via oxygen bridge from C1 to C4.

Why D is correct:

• It illustrates the α-1,4-glycosidic bond per the definition of oligosaccharide formation, where the anomeric OH of one xylose reacts with the C4 OH of the other.

Why the others are wrong:

• A shows no bond, just separate monomers.
• B depicts a β-1,4 linkage, incorrect for typical xylose dimer.
• C illustrates hydrolysis, adding water instead of forming the bond.

Final answer: D