Plz help After the Civil War ended, Yankees and carpetbaggers from the North wasted no time in exploiting the weakened South. What was once a proud society that stood up for traditional values and Christian ethics had been tainted by the influx of amoral entrepreneurs and Republican opportunists that had little business setting foot anywhere south of the Mason-Dixon line. -Sam Goethals, Ph. D. (1996)

What aspect of the source above most clearly compromises its credibility?

A. Its author lacks qualifications on the subject matter.
B. It is a secondary, rather than primary, source. C. It is biased in favor of a southern point of view.
D. It focuses on a topic that is not historical​