Rationale:
The oocyte (egg cell) remains viable for only 12–24 hours after ovulation.

The oocyte released from the ovary during ovulation travels to the fallopian tube, where fertilization is possible.

If fertilization by sperm does not occur within this 12–24 hour period, the oocyte gradually degenerates, and further conception is not possible.

Although sperm can survive in the female reproductive tract for 3–5 days, the oocyte has a very short lifespan, which is why the timing of conception is considered very important.

Therefore, from an examination perspective, the correct viability period of the oocyte is 12–24 hours.

Disclaimer:
This explanation is provided solely for the purpose of preparing for nursing and medical entrance examinations. Decisions in clinical practice should always be made by a qualified medical professional.