Why Can't the Carbon Dioxide Cycle Easily Correct for the Increasing

Why can't the carbon dioxide cycle easily correct for the increasing amounts of carbon dioxide introduced into our atmosphere by industrialization?

A) it operates far too slowly to correct for any short-term changes
B) pollution has stopped the carbon dioxide cycle from operating
C) the carbon dioxide cycle only influences carbon dioxide produced by natural sources
D) it operates far too quickly to correct for any short-term changes