You Are Working in the Field with Your Favorite Bacteria

You are working in the field with your favorite bacteria species,Bacterium BB.You carry out some experiments with Bacterium BB,and find that it can now degrade toluene and it is pathogenic! What happened?

A) Bacterium BB acquired degradative and virulence plasmids by horizontal gene transfer
B) Bacterium BB picked up fertility and Col-plasmids via conjugation
C) Bacterium BB was exposed to a bacteriophage which is now in its lytic phase
D) Bacterium BB was transformed with a resistance plasmid and a digestive plasmid
E) Bacterium BB sexually reproduced with another strain of bacteria that had both toluene-degrading gene and virulence gene