The incorrect statement from the following with respect to carbohydrates is:

• A
  All monosaccharides are reducing sugars.
• B
  The monosaccharide units obtained from hydrolysis of oligosaccharides are always the same.
• C
  Starch and cellulose are typical examples of polysaccharides,which are very high molecular weight compounds of more than ten monosaccharide units.
• D
  Open chain and cyclic structures co-exist at equilibrium that are responsible for certain properties as in the case of $D-(+)$-glucose.