$\left(+\right)-$sucrose is made up of

Methyl $\mathrm{D}$-glucoside on reaction with ${\mathrm{HIO}}_4$ consume two moles of the reagent and produces the dialdehyde $\left(\mathrm{A}\right)$ and one mole of $\mathrm{HCOOH}$

${\mathrm{HOCH}}_2\mathrm{-}\underset{\stackrel{|}{\mathrm{CHO}}}{\mathrm{CH}}-\mathrm{O}-\underset{\stackrel{|}{\mathrm{CHO}}}{\mathrm{CH}}-{\mathrm{OCH}}_{\mathrm{3}}$

The result of this reaction proves that glucose has:

Following are the structure of $\mathrm{D}-$glucose and $\mathrm{D}$-galactose

Which of the statement is correct about these compounds: 

The product formed in the reaction is:

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{CHOHCOC}}_6{\mathrm{H}}_5\stackrel{{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NHNH}}_2\left(\mathrm{excess}\right)}{\to }$