Is the following statement correct or incorrect? 

People with type AB blood can receive type A blood and donate type B blood.

Between chitin and chitosan, determine the main structural differences.

Chondroitin sulfate C, a component of cartilage, is a polymer that is joined together via β-1,4'-glycosidic linkages. It is composed of alternating D-glucuronic acid and N-acetyl-D-galactosamine subunits, with the sulfate group attached to carbon 6 in D-galactosamine. Draw the repeating units of chondroitin sulfate C.

For the following polysaccharides, determine the main structural differences.

Propose a reagent(s) for the conversion shown below. [Note: The glycoside linkage is unstable in acid.]