The correct option is B DNA amplification
The purpose of polymerase chain reaction is DNA amplification. The polymerase chain reaction (PCR) technique was developed by Kary Mullis in 1985, which is extremely powerful. It generates microgram (μg) quantities of DNA copies (upto billion copies) of the desired DNA (or RNA) segment, present even as a single copy in the initial preparation, ina matter of just a few hours.