Why Is It Unlikely That Genetically Engineered Strains of Bacteria

Why is it unlikely that genetically engineered strains of bacteria would pose a threat to the environment?

A) Genetically engineered bacteria cannot survive exposure to UV radiation.
B) Genetically engineered strains of bacteria are strictly regulated, making accidental release unlikely.
C) Genetically engineered strains of bacteria cannot survive exposure to oxygen.
D) Genetically engineered strains of bacteria are poor competitors of wild strains.
E) Genetically engineered strains of bacteria require supplemental nutrients to survive.