One of the following is an incorrect statement. Point out the incorect one.

• A

  ${\mathrm{H}}_2{\mathrm{O}}_2$ decomposes rapidly in presence of ${\mathrm{MnO}}_2$ 

• B

  Ice at its melting point is lighter than water because ice crystals have hollow hexagonal arrangement of ${\mathrm{H}}_2\mathrm{O}$ molecules.

• C

  ${\mathrm{D}}_2\mathrm{O}$ will have maximum density at $11.5^0\mathrm{C}$

• D

  Water gas contains greater proportion of CO than that of ${\mathrm{H}}_2$