A: Hair follicle
B: Ducts of the glands
C: Secretory parts of the glands (the cells are bigger and lighter than those making the wall of the duct. Be careful, the little dark dots in the bottom photo are nuclei of cells).

The sebaceous glands are classified as simple branched alveolar glands.
The ducts connecting the secretory parts to the hair follicle do not ramify (--> simple).
The secretory parts are shaped like little bags (--> alveolar or ascinar).
Several bags (at least two bags on the right side), share the same duct (--> branched).

D is the reticular layer of the dermis. The tissue here is connective proper dense irregular.