A researcher wants to stitch two fragments of DNA, "A" and "B" (shown in the figure below), using PCR. She uses primer pairs "a" and "b" to amplify DNA "A". Thereafter, she mixes equal concentrations of PCR amplified "A" and DNA "B" to set up a PCR using primers "a' " and "c".
The plus strand sequences of the two DNA fragments are given below ("...." stands for any of the four nucleotides):
A : 5'-AGAGAGAGAGAGAGAG.......GAGAGAGAGAGAGAGAGAGAG-3'
B: 5'-AGCTTGCATGCCTGCAGGTCGACT.......TAGACGATGA - 3'
Which one of the following options represents the correct sequence of primer "b"?
1
5'-CTCTCTCTCTCTCTCTCTTCGAACGTACGGACGTCCAGCTGA-3'
2
5'-AGTCGACCTGCAGGCATGCAAGCTTCTCTCTCTCTCTCTC-3'
3
5'-AGCTTGCATGCCTGCAGGTCGACTCTCTCTCTCTCTCTCTC-3'
4
5'-AGTCGACCTGCAGGCATGCAAGCTGAGAGAGAGAGAGAG-3'