Pathogens Have Four Ways to Resist Antibiotics: 1) Antibiotic Can't

Pathogens have four ways to resist antibiotics: 1) antibiotic can't get through cell membrane, 2) produce an enzyme that breaks down the antibiotic, 3) alter the structure of the antibiotic's target so it's not vulnerable, 4) pump out the antibiotic. How do these changes in the pathogens happen so they become resistant?

A) These changes are the result of repeated exposure to the antibiotic.
B) These changes are the result of genetic mutations.
C) Repeated horizontal gene transfer
D) Reproducing quickly in the presence of the antibiotic
E) Cross-breeding between pathogens