Observe the figure and answer the following questions:

Identify the statements which are true for oogenesis. 

A. Large number of primary follicles degenerate during the phase from birth to puberty.
B. Antrum a fluid filled cavity surrounded by a new theca is seen in primary follicles.
C. At puberty only 6 × 10⁵ - 8 × 10⁵ primary follicles are left in each ovary.
D. Oogonia are formed in fetal ovary.

Choose the the correct answer from the options given below:

A and D only

The correct answer is Option (2) → A and D only

The process of formation of a mature female gamete is called oogenesis. 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. Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle. A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty only 60,000-80,000 primary follicles are left in each ovary. The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles. The secondary follicle soon transforms into a tertiary follicle which is characterised by a fluid filled cavity called antrum. The theca layer is organised into an inner theca interna and an outer theca externa.