In a transformation experiment, a sample of E. coli bacteria was mixed with a plasmid containing the gene for resistance to the antibiotic ampicillin (ampr). Plasmid was not added to a second sample. Samples were plated on nutrient agar plates, some of which were supplemented with the antibiotic ampicillin. The results of E. coli growth are summarized below. The shaded area represents extensive growth of bacteria; dots represent individual colonies of bacteria.
1. Wildtype + No Amp: Lawn
2. Wildtype + Amp: No growth
3. Plasmid + No Amp: Lawn
Which of the following best explains why there is no growth on plate II?
A. The initial E. coli culture was not ampicillin-resistant.
B. The transformation procedure killed the bacteria.
C. Nutrient agar inhibits E. coli growth.
D. The bacteria on the plate were transformed.