Select the statements that correctly describe the process of oogenesis:

A. Oogenesis starts with the formation of primary oocytes during fetal development, which remain in prophase I until puberty.

B. Each month, a single primary oocyte resumes meiosis, completing meiosis I and forming a secondary oocyte.

C. The secondary oocyte is arrested in metaphase II and only completes meiosis II if fertilization occurs.

D. At the time of ovulation, the secondary oocyte is the product of meiosis I and is immediately ready to undergo fertilization.