Which Functional Assay Result Is Positive for HIT? (High Concentration

Which functional assay result is positive for HIT? (high concentration of heparin = 100 U/mL, low concentration = 0.1 U/mL)

A) Platelet aggregation is absent in the saline control and with the high concentration of heparin, but does occur with the low concentration of heparin.
B) Platelet aggregation occurs in the saline control and the high and the low concentrations of heparin.
C) Platelet aggregation is absent in the saline control but does occur in the high and low concentrations of heparin.
D) Platelet aggregation is absent in the saline control and the low concentration of heparin, but does occur in the high concentration of heparin.
E) A and D