Which of the Following Statements Accurately Describes the Change in CO₂

Multiple Choice

Which of the following statements accurately describes the change in CO₂ in the atmosphere since the turn of this century?

A) CO₂ has increased in the first half of the century, and decreased in the last half
B) CO₂ has remained at about the same concentration from year to year
C) CO₂ has been steadily increasing in concentration
D) CO₂ has been steadily decreasing in concentration