Answer:
Option D
Explanation:
Ice can assume a larger number of different crystalline structures, more than any other known material. At ordinary pressure, the stable phase of ice is called ice 1. There are two closely related variants of ice 1: hexagonal ice Ih, which has hexagonal symmetry and cubic ice Ic, which has a crystal structure similar to diamond.
Ice Ih is the normal form of ice; ice Ic is formed by depositing vapour at very low temperatures (below 140 K)
