Answer:
The correct answer is: C) immune system.
Step-by-step explanation:
The immune system is the system that maintains our body healthy by fighting pathogens like viruses and bacteria.
HIV, abbreviated from Human Immunodeficiency Virus, is a retrovirus that transmits through sexual contact and blood transfusion. If left untreated, it can cause AIDS (acquired immunodeficiency syndrome) over time, which deeply impairs the immune system, allowing opportunistic infections and cancers to appear and cause death.
HIV infects helper T cells, macrophages and dendritic cells (these cells are of great importance for the immune system). When the number of helper T cells heavily decreases, the cell-mediated immune response becomes impossible and the body begins to suffer immunosuppression.