The Graph Below Shows Atmospheric Concentration of CO₂ as Recorded

The graph below shows atmospheric concentration of CO₂ as recorded at the Mauna Loa Observatory. From the graph we can see that there are seasonal fluctuations in CO₂ concentrations that correspond with:

A) Plants taking up more carbon dioxide in the growing season.
B) Temperatures fluctuating between day and night.
C) Plants releasing more carbon dioxide in the growing season.
D) Cattle producing more methane in the summer when they are grazing.