C prioritizing IS CORRECT PLEASE DO C
Macrophages are the phagocytes that are present in the medulla of the lymph node. They engulf the pathogens like viruses, bacteria etc. They originate from the bone marrow and also act as antigen presenting cells (APC) for T-cells, and kill the pathogen after activation by T-cells.
Im pretty sure the heart rate decreases and the breathing increases. I'm not sure about the others.