In 2005, a strain of extremely drug-resistant bacteria was isolated from a man in New York City. Public health officials braced themselves for many more cases, but they never appeared. What is the most likely explanation?

A) The strain must have reverted back to a sensitive strain in order to keep infecting more people.
B) The strain may have been less fit in other ways and thus not successful in the population.
C) The strain must have become extinct.
D) The strain must have been dormant and was waiting for the right conditions to reappear.