Which of the Following Is NOT Part of Plant Defense

Which of the following is NOT part of plant defense systems against pathogens?

A) Protein receptors detect a broad class of molecules produced by many pathogens and mount defense mechanisms.
B) R proteins inside plant cells recognize AVR proteins from pathogens.
C) Plants reinforce barriers, such as by closing stomata and reinforcing cell walls.
D) Cells surrounding the infection site produce reactive oxygen species.
E) Plants produce AVR proteins when invaded by a pathogen.