Snow Does Not Immediately Melt Away on a Mild Spring

Snow does not immediately melt away on a mild spring day because:

A) shortwave radiation from the sun is absorbed but not re- radiated as longwave.
B) snow is more resistant to melting when it's been sitting on the ground for a long time.
C) the high albedo of the snow keeps air temperatures cooler.
D) snow allows more longwave radiation to be absorbed by the air.