Which Statement Reflects the Finding of the Study Conducted by Bushman

Which statement reflects the finding of the study conducted by Bushman and Wells (2001) on narrative reviews and meta-analyses?

A) Knowledge of meta-analysis can improve the way that one interprets information for literature reviews.
B) In a meta-analysis, it is difficult to provide the type of general conclusion that can be reached with the traditional literature review.
C) By organizing and evaluating previously published material, authors of literature reviews consider the progress of research toward clarifying a problem.
D) The conclusions in meta-analyses and literature reviews are based on the objective impressions of the reviewer.