In humans, mammary gland is divided into ____________ lobes.

Correct option is D

A functional mammary gland is characteristic of all female mammals. The mammary glands 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. The cells of alveoli secrete milk, which is stored in the cavities (lumens) of alveoli.