Bacterial infections have become much more of a threat to human health due to which of the following?

A)the increased use of antibiotics
B)an increase in acquired antibiotic resistance by innocuous strains
C)horizontal transfer of pathogenicity
D)an increased use of antibiotics coupled with an increase in acquired antibiotic resistance by innocuous strains
E)an increased use of antibiotics,horizontal transfer of pathogenicity,and an increase in acquired antibiotic resistance by innocuous strains