Increasing Atmospheric Carbon Dioxide Since 1950

Multiple Choice

Increasing atmospheric carbon dioxide since 1950.Monthly average CO2 measured at Mauna Loa Observatory in Hawai''i.The highest and lowest months (usually May and October) are plotted for each year;black line shows the 5-year running average.

Which is true of the level of CO₂ in our atmosphere?

A) CO2 is reached 400 ppm in approximately 2013.
B) The rate of increase leveled out in 1976.
C) The level of CO2 was much higher in 1955 than today.
D) The level of CO2 is decreasing at 3.1% per year.
E) The levels of CO2 have greatly fluctuated over the past 50 years.