What do we learn from this plot? A. CO2 measures increase monotonically from 1959 to 1997. B. CO2 measures are higher in the summer and the yearly average increased from 1959 to 1997. C. CO2 measures...

What do we learn from this plot?

A. CO2 measures increase monotonically from 1959 to 1997.

B. CO2 measures are higher in the summer and the yearly average increased from 1959 to 1997.

C. CO2 measures appear constant and random variability explains the differences.

D. CO2 measures do not have a seasonal trend.