Correct option is B
Explanation-
We are given a template DNA sequence
This means the actual target sequence lies between:
Start: A T C G A C T A G
End: C C T A A T G C A G
We need to select two primers:
Primer 1: Binds to the start of the bottom (template) strand — it should be complementary to the 3' end of the top strand, and run 5' to 3'
Primer 2: Binds to the end of the top strand — it is complementary to the 3' end of the bottom strand, and runs 5' to 3'
Option b:
Primer 1: 5′-C T T G C A T-3′
→ This binds to the 3′ end of the bottom strand, complementary to A T G C A A G, which is the reverse complement of the 3' end of the top strand.
Primer 2: 5′-A T C G G A C-3′
→ This binds to the top strand, at the 5' end, complementary to the start region.
Together, these primers flank the target region correctly and face inward, allowing amplification.
Incorrect Options:
Option a: Primers point away from each other or are not complementary to the correct ends.
Option c: Both primers bind in the same region or orientation.
Option d: Similar issue — primers do not properly flank the target region.
Final Answer: Option b is correct
