The correct option is B secondary oocyte
Graafian follicle is a mature follicle which develops from the tertiary follicle. It consists of a secondary oocyte formed from the primary oocyte at puberty.
During ovulation, Graafian follicle ruptures to release the secondary oocyte from the ovary.
The secondary oocyte divides and forms ovum (female gamete) after coming in contact with the sperm.