A 40-yr-old firefighter suffers severe burns when a roof collapses. He is put on a ventilator in the intensive care unit and he unfortunately develops Gram-negative sepsis (bacteria circulating and replicating in the bloodstream), followed by septic shock. Which VF below is the most likely cause of his shock?

A) Lipase exoenzymes
B) Adhesion molecules (pili and fimbriae)
C) An A-B subunit toxin
D) Lipopolysaccharide (LPS/endotoxin)