The Primary Purpose for DNA Complexation with Cationic Polymers and Lipids

The primary purpose for DNA complexation with cationic polymers and lipids in chemical methods of gene transfer is:

A) To confer controlled release feature of gene delivery system.
B) To protect DNA from serum and tissue nucleases.
C) To overcome endothelial cell barrier.
D) To confer preferential accumulation of gene delivery systems in RES tissues.
E) To facilitate cytoplasmic and nuclear transport of DNA once being inside cells.