Final answer:
The ideal target region for primers in PCR is exons, as they contain the protein-coding sequences that will be used to produce a polypeptide.
Step-by-step explanation:
In a PCR (Polymerase Chain Reaction), the ideal target region for the primers to bind to is the exon, because exons are the protein-coding sequences in eukaryotic genes that are transcribed into RNA and then spliced together to form mature mRNA, which codes for a polypeptide. Introns, on the other hand, are non-coding sequences that are removed from the primary transcript mRNA before it is translated into protein. Therefore, the correct answer is a) Exons.