Answer:
C. serous cells and mucous cells
Explanation:
Salivary glands consist of serious acini and/or mucous acini. The serous acini represent the serous fluid secreting part of the salivary glands and is composed of serous cells. The mucous acini are made of mucous secreting cells.
The parotid salivary glands consist of serous cells only while the sublingual glands and submandibular cells have both serous and mucous cells.