Bacterial DNA is referred to as naked because it is not associated with:

In eukaryotes, DNA is wrapped around histone proteins to form chromatin, providing structural organisation. In prokaryotes (bacteria), the chromosomal DNA is not packaged with histone proteins (though it associates with some nucleoid-associated proteins, these are not the histone-type packaging proteins). Hence, bacterial DNA is described as 'naked' because it lacks the typical histone protein association seen in eukaryotic chromosomes. Therefore, the correct answer is proteins.