E Coli O157:H7 Was First Observed in Fast-Food Hamburger Meat

E. coli O157:H7 was first observed in fast-food hamburger meat. More recently, it has been associated with contamination of spinach and other vegetables. How did this spread from meat to vegetables happen?

A) E. coli O157:H7 picked up genes for plant virulence.
B) E. coli O157:H7 can grow as a plant endophyte.
C) E. coli O157:H7 has become a psychrotroph and can grow in refrigerated foods.
D) E. coli O157:H7 produces toxins that can survive on plant material.
E) E. coli O157:H7 has lost genes needed to grow in meat.