In humans, mammary gland is divided into _______ lobes.

The correct answer is Option (4) → 15-20

Each mammary lobe holds clusters of alveoli. The cells of the alveoli secrete milk, which collects in their cavities. The milk then flows through the mammary tubules, the mammary ducts, the mammary ampulla and the lactiferous duct, through which the baby sucks it out.

NCERT Extract:
The Female Reproductive System – “… A functional mammary gland is characteristic of all female mammals. The mammary glands are paired structures (breasts) that contain glandular tissue and variable amount of fat. The glandular tissue of each breast is divided into 15-20 mammary lobes containing clusters of cells called alveoli (Figure 2.4).”