Which one of the following reflects back more sunlight as compared to other three?

1. A

   Sand Desert

   A sand desert has a moderately high albedo compared with green vegetation, but sand still absorbs a large share of incoming solar radiation and heats strongly. Fresh snow reflects far more sunlight than desert sand. This option is therefore not the key.

2. B

   Paddy crop land

   Paddy crop land is a vegetated, often wet surface with a low albedo; water and chlorophyll absorb much of the visible and near-infrared energy. It reflects less sunlight than desert, prairie or snow. This option is not the key.

3. C

   Land covered with fresh snow

   Land covered with fresh snow reflects back more sunlight than the other three surfaces. Fresh snow has a very high albedo, commonly of the order of about 0.8 or higher, so most incoming short-wave radiation is sent back to space. That is why snowfields stay cooler and contribute to Earth’s planetary reflectivity. Among sand desert, paddy land, prairie and fresh snow, fresh snow is the strongest reflector, so this is the official key.

4. D

   Prairie land

   Prairie land is grassland with a moderate-to-low albedo, higher than a dense crop or water surface but far below fresh snow. It does not out-reflect snow or typically even bright desert. This option is not the key.

Summary. Official key is (c) Land covered with fresh snow. Albedo measures the fraction of incoming sunlight reflected by a surface. Fresh snow has the highest albedo of the four listed covers. Desert sand reflects more than green crops but much less than snow. Paddy and prairie absorb a large share of solar energy. Only (c) is correct.