One mole of $2-$methylbuta$-1, 3-$diene on ozonolysis gives:

• A
  $2$ moles of methanal and $1$ mole of propanone.
• B
  $2$ moles of methanal and $1$ mole of $2-$oxopropanal.
• C
  $1$ mole of methanal,$1$ mole of ethanal,and $1$ mole of propanone.
• D
  $2$ moles of ethanal and $1$ mole of $2-$oxopropanal.