The tertiary follicle changes into
a)	Graafian follicle	b)	Oocyte
c)	Megaspore mother cell	d)	ovum

(a)

A tertiary follicle changes into the mature follicle or Graafian follicle. The secondary oocyte forms a new membrane called zona pellucida surrounding it. The Graafian follicle ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation