The figure given below shows the sectional view of an ovary. Select the option which gives the correct identification of the marked structure ($A$ to $D$) and its feature.

• A
  $A$: Primary follicle,it is also called a gamete mother cell.
• B
  $B$: Corpus luteum,it cannot be formed and added after birth.
• C
  $C$: Graafian follicle,a mature follicle which ruptures to release a secondary oocyte.
• D
  $D$: Tertiary follicle,a large number of these follicles degenerate during the phase from birth to puberty.