Plasmid DNA isolated from a bacterial lysate was digested with restriction enzymes X and Y. The preparations were then electrophoresed on agarose gels producing the DNA fragment patterns shown in the figure.
For the purpose of estimating fragment length, sizing markers were run simultaneously (lane 1). Other preps were: uncut DNA (lane 2), enzyme X-treated DNA (lane 3), enzyme-Y treated DNA (lane 4), DNA treated with enzymes X and Y simultaneously (lane 5).
Based on the fragment patterns of the panel of digests, which of the following is the MOST likely restriction map?