Which of the following events would cause the greatest reduction inthe nitrogen availablity to the root system of a plant?
A. Increase the activity of nitrogen-fixing bacteria in thesoil.
B. Increase the activity of nitrifying bacteria in thesoil.
C. Increase the activity of denitrifying bacteria in thesoil.
D. Decrease the activity of ammonifying bacteria in thesoil.
E. Both C and D