The correct answer is: Prokaryotes do not store their genes in a nucleus like eukaryotes do.
This reflects a fundamental difference between prokaryotic and eukaryotic organisms, as prokaryotes have their genetic material located in the cytoplasm, while eukaryotes have their DNA housed within a nucleus.
The other options provided contain incorrect statements about how gene regulation occurs in prokaryotes and eukaryotes. For example, not all eukaryotes use operons, and splicing of exons and introns is a characteristic of eukaryotic mRNA processing, not prokaryotic.