Why Might Excess CO₂ in the Atmosphere Heat Up the Earth

Why might excess CO₂ in the atmosphere heat up the earth?

A) Because CO₂ increases Earth's "reflectivity."
B) Because CO₂ is an important participant in the photosynthesis process.
C) Because CO₂ absorbs, or traps, infra- red radiation.
D) Because CO₂ reacts with and thus destroys the ozone layer.
E) Because CO₂ absorbs, or traps, ultra- violet radiation.