UASs (upstream activating sequences) are DNase hypersensitive. This means that ________.

A) a UAS is constitutively open
B) more than one strand of DNA exists in each UAS
C) each UAS is likely to be single-stranded
D) each UAS has more histone-binding sites than non-UAS sites
E) any given UAS is composed of a double-stranded site with a bound repressor