When $H_{2}O_{2}$ is shaken with an acidified solution of $K_{2}Cr_{2}O_{7}$ in the presence of ether, the ethereal layer turns blue due to the formation of

• A
  $Cr_{2}O_{3}$
• B
  $CrO_{4}^{2-}$
• C
  $Cr_{2}(SO_{4})_{3}$
• D
  $CrO_{5}$