Final answer:
Plasma cells are classified as agranulocytes because they lack prominent granules in their cytoplasm, and they play a significant role in the immune system by producing antibodies.
Step-by-step explanation:
Plasma cells are a type of white blood cell, specifically a form of lymphocytes, which are part of the immune system. They are not granulocytes because, unlike granulocytes, they do not contain prominent granules in their cytoplasm. Instead, plasma cells are classified as agranulocytes. These cells are important because they are B cells that have differentiated in response to antigen binding, and they specialize in producing and secreting antibodies. Therefore, the answer to whether plasma cells are granulocytes or agranulocytes is: 2) Agranulocytes.