Scientists developed an antibiotic to fight harmful bacteria that cause

infections. After several years of use, the antibiotic became less effective.

Which of the following caused the antibiotic to become less effective?

A Bacteria that were resistant to the antibiotic survived to produce more

resistant bacteria.

B Bacteria that were not resistant to the antibiotic began to produce

resistant bacteria through meiosis.

C Bacteria that were not resistant to the antibiotic learned how to protect

themselves from the antibiotic.

D Bacteria that were resistant to the antibiotic lost their resistance with

repeated exposure to the antibiotic.