What Does Polymerase Chain Reaction (PCR)allow Us to Do

What does polymerase chain reaction (PCR) allow us to do?

A) use genetic methods to explore the origins and movements of populations and study small amounts of DNA in ancient skeletons
B) make only a few copies of tiny sequences of DNA for study
C) reach conclusions about DNA sequences through a series of tests without viewing actual copies of the DNA
D) map the dental formulas of skeletons and has primarily led to research centered on the diet of human's ancestors