Cipro, an Antibiotic That Is Taken Orally, Has Been Recently

Cipro, an antibiotic that is taken orally, has been recently reevaluated for its impact on intestinal microbial flora; what best summarizes the findings?

A) Not surprisingly, there was virtually no effect; otherwise, human trials would have indicated that Cipro was unsuitable for human use.
B) A small but insignificant reduction in species diversity followed each course of antibiotics, but test participants quickly reestablished a normal intestinal community.
C) A single course of antibiotics was tolerated well by the majority of test participants, but a second course of antibiotics administered shortly after the first caused an extensive and prolonged change.
D) Intestinal microbial are particularly sensitive to Cipro; their populations crashed almost immediately after the first dose was taken.