With Both Bacterial and Eukaryotic Cells Constantly Dying and Breaking

With both bacterial and eukaryotic cells constantly dying and breaking down around us, and with a tremendous load of fragmentary DNA washing around in the fluid world, why aren't genes being transferred among various living organisms at a massive scale daily?

A) DNA that is not protected inside a protein coat or membrane is very vulnerable.
B) Living cells maintain a very effective barrier to the introduction of large molecules.
C) Since a vector appears necessary to snatch up DNA from one protected source and inject it into a cell, "naked" DNA is apparently vulnerable and unable to cross membranes easily.
D) All of the choices are correct.
E) None of the choices are correct, since DNA is readily exchanged among all organisms in nature.