In humans females at the time of birth, the stage of cell cycle of oocyte is :

Prophase-I

The correct answer is Option (1): Prophase-I

The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis.

Oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each fetal ovary; no more oogonia are formed and added after birth. These cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage, called primary oocytes. When a female hits puberty these arrested primary oocytes (2n) completes meiosis I to form large secondary oocyte (n) and small first polar body(n)