Lead Time Bias Is Best Described As

Lead time bias is best described as:

A) an apparently lower survival rate among persons screened compared to an unscreened group.
B) an actually longer survival time for persons identified during a screening program because they were given an effective treatment.
C) a similar survival time for persons identified during a screening program relative to persons who are diagnosed by clinical symptoms.
D) an apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease.