Final answer:
The oocyte is in metaphase II of meiosis II after ovulation and before fertilization. Upon fertilization, it quickly completes meiosis II to form a diploid zygote. Therefore, the correct option is C
Step-by-step explanation:
The oocyte after it is ovulated and before the egg is fertilized is in the stage known as metaphase II. This stage is part of meiosis II where the secondary oocyte remains arrested until fertilization occurs. When fertilization by a sperm takes place, the secondary oocyte quickly completes meiosis II, releasing a second polar body and forming the diploid zygote with genetic material from both the male and female gametes.