Correct Option: B

The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. By their percentage contribution to the greenhouse effect on Earth the four major gases are: water vapor, 36–70%, carbon dioxide, 9– 26%,methane, 4–9% and ozone, 3–7%.