Concept:Testing donated blood helps avoid passing HIV from one person to another during a blood transfusion.
Explanation:Before a transfusion, every unit of donated blood is screened for infections such as HIV.
If the blood sample shows the presence of HIV, that blood is rejected and not used.
This ensures that a patient receiving blood is not infected through the transfusion.
Testing cannot cure, remove, or completely eliminate HIV from a person who already has it.
It only reduces the risk of transmitting the virus through blood.
Therefore, the main benefit of testing blood before transfusion is to stop the spread of HIV from donor to patient.
Answer:D. prevent HIV