There has been an outbreak of an antibiotic-resistant bacteria in a hospital. Previously, all patients were susceptible to the antibiotic. Five patients have recently become infected, but it is unclear where the resistant bacteria came from and how it spread among the patients. To investigate this, you sequence DNA from bacteria sampled from each of the five infected patients. This is a short piece of DNA found to vary among the five bacteria samples:
a) GGATCCAGT
b) GGGTCCAGT
c) GGATTCAGT
d) GGATCCACT