The High Temperatures in the Thermosphere Occur Because

The high temperatures in the thermosphere occur because

A) infrared radiation from the ground heats this layer more than any other layer.
B) carbon dioxide has accumulated to very high levels in this layer.
C) it is in direct contact with high energy solar radiation.
D) high intensity solar radiation causes strong chemical reactions with ozone,and this heats the layer to very high temperatures.
E) methane is such an effective greenhouse gas.