Researchers investigating the effects of expert testimony on jurors' decisions have generally found which of the following?

a$.$ Jurors evaluated the testimony of the experts based on the expert's qualifications, the quality of the expert's reasoning, and the expert's impartiality.

b$.$ The most important part of the expert's presentation is information regarding the expert's qualifications.

c$.$ An expert's appearance significantly affects decisions.

d$.$ An expert's personality significantly affects decisions.