The correct option is B 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, in a matter of just a few hours.
Replication is a natural process, which occurs within organisms and uses RNA primers whereas in the case of amplification it uses DNA primers and is an artificial process which requires heating and cooling.