Answer :
The answer is:
Penicillin was so heavily prescribed by doctors that it led to certain, more fit, strains of bacteria to be able to survive.
Penicillin was so heavily prescribed by doctors that it led to certain, more fit, strains of bacteria to be able to survive.
I just did this one, it is D, Penicillin was so heavily prescribed by doctors that it led to certain, more fit, strains of bacteria to be able to survive.