Using PCR, a Student Wants to Amplify a Sequence of Known

Multiple Choice

Using PCR, a student wants to amplify a sequence of known DNA from a genomic DNA sample. The two primers are both designed to pair with sequences that have a 40% GC content. Using a particular set of denaturation temperatures, annealing temperatures, and extension temperatures, the experiment does not produce the expected single DNA fragment of a single known size, but instead a set of fragments of varied sizes. Which of the following could account for these results?

A) The annealing temperature was too low so that the primers can bind with multiple genomic sequences that contain some mismatched bases.
B) The denaturation temperature was too high so that the primers can bind with each other as well as with multiple genomic sites containing mismatches.
C) The extension temperature was too low so that many fragments were terminated before the full fragment was replicated.