The Figure Below Shows a Gel with Escherichia Coli DNA

The figure below shows a gel with Escherichia coli DNA fragments separated by size. The marker lanes help to locate the transcription start following the promoter region of a gene encoding for glutamate decarboxylase (GadA) . There are five lanes from an experiment in which varying amounts of the protein GadX were added to DNA prior to treatment with DNase I. What do the roman numeral boxes indicate?

A) change RNA to DNA.
B) topoisomerases-binding regions
C) thus not protected
D) translational start
E) GADF-binding site