Given below is a diagrammatic cross-section of a single loop of the human cochlea. Which one of the following options correctly represents the names of three different parts?

• A
  $D$: Sensory hair cells,$A$: Endolymph,$B$: Tectorial membrane.
• B
  $A$: Perilymph,$B$: Tectorial membrane,$C$: Endolymph.
• C
  $B$: Tectorial membrane,$C$: Perilymph,$D$: Sensory hair cells.
• D
  $C$: Endolymph,$D$: Sensory hair cells,$A$: Serum.