Use the Following to Answer Questions

Use the following to answer questions
A scientist carries out a ligation reaction designed to insert a foreign piece of DNA into a plasmid that contains the front end of the lacZ gene within the multiple cloning site (MCS) . He carries out three transformations in parallel with lacZ^- bacteria. The three transformations (i, ii, and iii) contain the following:
i. sterile water
ii. a sample of the original plasmid
iii. the ligation reaction
He then plates the transformations on medium containing X-gal and ampicillin.
-The scientist observed colonies on plate (i) . Which of the following might be reasons(s) for this? (Select all that apply.)

A) The plasmid he used has a kanamycin resistance marker instead of an ampicillin resistance marker.
B) He transformed cells that were not actually ampicillin sensitive.
C) Too high a concentration of ampicillin was added to the plates.
D) Too low a concentration of ampicillin was added to the plates.
E) The water sample was contaminated with the original plasmid.