A) locate the specific sequence that is going to be amplified
B) allow the DNA polymerase to bind to the DNA
C) denature the DNA
D) A and B are both correct
E) A and C are both correct
The answer is D.
In PCR amplification, the target DNA is first denatured by heating it up to about 94-98 degree Celsius. This open up the double stranded DNA so that the primer can bind to it in the next step of PCR. In PCR, the primer is specifically designed so that it can anneal to the target sequence, the sequence we want to amplify. After the primer anneals to the start of the target sequence, the DNA polymerase recognizes the primer, binds to the DNA, and synthesizes a new strand of DNA from the primer. This process is repeated over and over again until we have a large quantity of our target sequence.
As you can see from this description, the primer is specifically designed to locate the specific sequence that we want to replicate and help the DNA polymerase bind to the strand in a much more favorable manner. The denaturation of DNA is done by the high temperature in the beginning.
Thus, D is the correct answer.