An Antibiotic Is Given Repeatedly to Treat a Recurrent Ear

Multiple Choice

An antibiotic is given repeatedly to treat a recurrent ear infection. It worked initially but now is no longer effective. This indicates that the Streptococcus bacterium:

A) is very sensitive to the antibiotic.
B) is being treated with an antibiotic that has experienced a manufacturing error, making it infective.
C) experienced natural selection that has allowed the resistant Streptococcus to survive and multiply.
D) are infectious only if they are sensitive to the antibiotic.