Final answer:
An ovulated egg is viable and can be fertilized for approximately 12-24 hours. It contrasts with the longer viability of sperm, which can survive about 3-5 days in the female reproductive tract.
Step-by-step explanation:
The viability of an egg after ovulation is crucial for fertilization to occur. Once the egg is released from the ovary during the process of ovulation, it has a limited timeframe in which it can be fertilized by sperm. Sperm can survive in the fallopian tubes for about 3-5 days after ejaculation, enabling fertilization to occur even if intercourse happens a few days before ovulation. However, in contrast to sperm, an oocyte (egg) can survive for approximately 24 hours following its release during ovulation.
Based on this information, the correct answer to how long an egg is viable and capable of being fertilized after it is ovulated would be option A) 12-24 hours.