Answer:
D. released from the cell through the plasma membrane
Explanation:
Secretory proteins are produced in the rough endoplasmic reticulum from where it enters into the Golgi apparatus. In the Golgi apparatus, these proteins are modified and packed into the vesicles.
From the Golgi apparatus these secretory protein reaches the plasma membrane and release out of the cell through the membrane. These secretory proteins can be a hormone, antimicrobial peptides, enzymes, etc. They are called secretory protein because they are secreted to the extracellular region of the cell. Therefore the correct answer is D.
