The figure below shows the structure of a mitochondrion with its four parts labelled $(A), (B), (C)$ and $(D).$ Select the part correctly matched with its function.

• A
  $Part (D):$ Outer membrane - Gives rise to inner membrane by splitting.
• B
  $Part (B):$ Inner membrane - Forms infoldings called cristae.
• C
  $Part (C):$ Cristae - Possess single circular $DNA$ molecule and ribosomes.
• D
  $Part (A):$ Matrix - Major site for respiratory chain enzymes.