Which of the following layers in an antral follicle is acellular?

At the time of puberty, the primordial follicle starts to grow and the oocytes starts to enlarge. The surrounding follicular cells divide to become several layers thick and secrete a glycoprotein material which forms an acellular layer surrounding the oocytes called as the zona pellucida. The follicular cells are called as granulosa cells. Changes occur in the surrounding stromal cells which are now called as theca. Thus, the correct answer is option A.