In human females, at ovulation the Graafian follicle ruptures and rel…

The correct answer is Option (3) → Secondary oocyte

Oogenesis runs in stages. Oogonia form in the fetal ovary and enter meiosis, but stop at prophase I as primary oocytes. Inside the tertiary follicle the primary oocyte completes the first meiotic division and forms a large haploid secondary oocyte and a small first polar body. The Graafian follicle then ruptures and releases this secondary oocyte. The second meiotic division is completed only later, when a sperm enters the ovum.

Option (1) Oogonium — Incorrect. Oogonia are the gamete mother cells formed in the fetal ovary. They have already become primary oocytes long before puberty, so an oogonium is never released.

Option (2) Primary oocyte — Incorrect. The primary oocyte finishes the first meiotic division inside the tertiary follicle, before ovulation. What leaves the ovary is its product, the secondary oocyte.

Option (3) Secondary oocyte — Correct. At ovulation the Graafian follicle ruptures and releases the secondary oocyte (ovum). It has finished meiosis I but not meiosis II.

Option (4) Haploid ovum that has completed the second meiotic division — Incorrect. The second meiotic division is completed only when the sperm enters the ovum during fertilisation, in the fallopian tube. So the cell released at ovulation has not yet finished it.

NCERT Extract:
Gametogenesis – “… It is an unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body (Figure 2.8b). … The tertiary follicle further changes into the mature follicle or Graafian follicle (Figure 2.7). The secondary oocyte forms a new membrane called zona pellucida surrounding it. The Graafian follicle now ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation.”
Fertilisation and Implantation – “… The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane. This induces the completion of the meiotic division of the secondary oocyte. The second meiotic division is also unequal and results in the formation of a second polar body and a haploid ovum (ootid).”