When vegetation sprouts in the desert, it is a good sign but when the ice in the Arctic and Antarctic begins to turn green, there is something terribly wrong. Reports say that an iceberg, approximately the size of New York city, has broken off from the icy continent. An Argentine team discovered huge cracks in the polar ice caps. These developments can have serious implications. If polar ice fields melt, our coastal cities might be submerged, and sea levels across the world could rise between 3.65 and 6.09 metre in different parts of the earth. This is probably due to global warming.
Polar ice caps develop huge cracks because :

Options

A. of the movement of the earth
B. of the breaking off of icebergs
C. of the crowding of cities like New York
D. of rising temperatures