Suppose you are testing a treatment for AIDS patients and find that 75% respond well, whereas 25% show no improvement or a decline in health. You should

A) discontinue experimentation with this treatment because 25% of patients did not improve.
B) begin work on developing a new drug.
C) conclude that only 75% of AIDS patients should be treated.
D) review the results, modify the drug or the dosage, and repeat the experiment.
E) conclude that you have proven the effectiveness of the drug.