The Study of Ancient DNA (ADNA) Received a Significant Boost

The study of ancient DNA (aDNA) received a significant boost with the development of the polymerase chain reaction (PCR) technique -- a method for the accurate recovery of even minute amounts of DNA. This research advancement also created a new research problem;

A) now there are so many samples that could be tested, there is no way they can all be analyzed.
B) analysis is now only possible, worldwide, in three highly specialized lab.
C) there is now a much greater possibility of contamination of ancient DNA samples with DNA from lab workers.
D) the ancient DNA sequences recovered by the PCR technique are scrambled.
E) any ancient DNA recovered is damaged and degraded by the PCR technique.