During the latent stage of HIV disease, the viral load (amount of detectable virus in the blood) represents a "___ ___" that predicts the length of time until the onset of AIDS. If the viral load is = 10,000 viral copies/ml, onset is more than 10 years away. If the viral load is 100,000 viral copies/ml, onset is less than 10 years away.

a) Set Point
b) Danger Zone
c) Viral Threshold
d) Critical Level