One Way in Which Expert Testimony May Increase the Competence

One way in which expert testimony may increase the competence of jurors is by

A) facilitating judges' use of scientific jury selection.
B) leading jurors to be more critical of eyewitness testimony.
C) eliciting sentencing disparity.
D) modeling confidence,thus providing the jurors with a standard against which they can assess the confidence of non-expert witnesses.