A bacterial species will inevitably develop greater resistance within a few years to any antibiotics used against it, unless those antibiotics eliminate that species completely. However, no single antibiotic now on the market is powerful enough to eliminate bacterial species X completely. Which one of the following is most strongly supported by the statements above? ['Bacterial species X is more resistant to at least some antibiotics that have been used against it than it was before those antibiotics were used against it.', 'Bacterial species X will inevitably become more virulent in the course of time.', 'If any antibiotic now on the market is used against bacterial species X, that species will develop greater resistance to it within a few years.', 'It is unlikely that any antibiotic can be developed that will completely eliminate bacterial species X.']