Answer:
B. Hematopoietic cytokines
Step-by-step explanation:
The cytokines that are involved in the differentiation of the different formed elements of the blood called the Hematopoietic cytokines.
The Hematopoietic cytokines are classified as extracellular ligands. They help in the stimulation of hematopoietic cells (which are cells which form the blood) to differentiate it into the main types of blood cells.