Why might scientists often be hesitant to believe the results of a single experiment testing a particular treatment, even when the results are peer reviewed and statistically significant?

A) The experimental and control groups may be too alike.
B) The results may not be true for humans if the experiment used a model organism.
C) A single experiment may have eliminated most of the alternative hypotheses.
D) The experiment was likely to have had many biases that affected the results.