'Tuberculosis fights back with indestructible bacteria.' After having been almost eradicated in rich countries and controlled in the Third World, t...

'Tuberculosis fights back with indestructible bacteria.' After having been almost eradicated in rich countries and controlled in the Third World, the disease is spreading again, in a more threatening form: a drug-resistant variety. ('Folha de São Paulo' - 23/05/93).
This resistant strain of bacteria is the result of:
a) Mutagenic action of certain antibiotics.
b) Direct action of certain antibiotics on bacterial DNA.
c) Continuous exposure of bacteria to certain antibiotics that induce resistance.
d) Natural selection of bacteria accustomed to the antibiotic.
e) Selection of mutant bacteria strains resistant to antibiotics.