Carbon dioxide is a gas but silica is a solid because
A. Carbondioxide is composed of discrete covalent `CO_(2)` molecules where as silica has continuous tetrahedral structure
B. `CO_(2)` molecules are lighter than `SiO_(2)` molecules
C. `CO_(2)` is more acidic than `SiO_(2)`
D. Melting point of silica is very high
