Final answer:
Erythropoiesis takes place in the bone marrow, specifically the red bone marrow, under the stimulus of erythropoietin, a hormone primarily released by the kidneys. The correct answer to the question is C. bone marrow.
Step-by-step explanation:
Erythropoiesis is the process of producing erythrocytes, or red blood cells. This process takes place in the bone marrow, specifically within the red bone marrow, which is a loose collection of hematopoietic cells. The erythropoietin (EPO), a hormone released primarily by the kidneys, stimulates the bone marrow to produce red blood cells when there is a need for more oxygen in the body or when oxygen levels are low. For example, when moving to higher altitude or engaging in aerobic exercise, the kidney increases EPO production. The correct answer to the question is C. bone marrow.
The spleen and liver are involved in hematopoiesis during embryonic development, and later, the spleen has functions related to blood cells, but it is not the primary site of erythropoiesis. Erythropoietin is indeed crucial for this process but is a hormone, not a location. Plasma is the liquid component of blood and does not generate blood cells.