All of the Following Statements About Atmospheric Carbon Dioxide Levels

All of the following statements about atmospheric carbon dioxide levels are true,EXCEPT

A) levels are currently measured directly from the air.
B) historic levels are measured by examining air bubbles trapped in ice cores.
C) historic levels of CO₂ reached present-day levels only twice before.
D) CO₂ levels cycle in patterns that correlate with major ice ages.
E) since the late 1800s,atmospheric CO₂ has increased 35%.