Why Are Changes in the Global Carbon Cycle Important

Why are changes in the global carbon cycle important?
I. Burning reduces available carbon for primary producers and, therefore, primary consumers.
II. Deforestation and suburbanization reduce an area's net primary productivity.
III. Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate.
IV. By using fossil fuels, we are destroying a nonrenewable resource.

A) only II, III, and IV
B) only II and IV
C) only I, II, III, and IV
D) only I, II, and IV
E) only I and III