Which of the Following Is Not a True Statement

Which of the following is not a true statement?

A) When the Earth's temperature increases, the rate of decomposition of organic soil increases adding more carbon dioxide into the atmosphere
B) When more carbon dioxide enters the atmosphere, the Earth's overall mean temperature stabilizes
C) Carbon dioxide emissions from fires, factories, energy production plants, and transportation machines have caused the overall concentration to carbon dioxide to reach its highest level in over 420,000 years
D) The carbon dioxide emissions to Earth's climate have caused the Earth's mean annual temperature to increase by 0.8°C