Palaeontologists unearthed a human skull during excavation. A small fragment of the scalp tissue was still attached to it. Only little DNA could be extracted from it. It the genes of the ancient man need to be analysed, the best way of sufficient amount DNA from this extract is
A. hybridising the DNA with a DNA probe
B. subjecting the DNA to polymerase chain reaction
C. Sujbection the DNA to gel electrophoresis
D. treating the DNA with restriction endonucleases
