The table gives the physical properties of four substances. Which substance has a giant covalent structure?
- Amelting point $-119\,^\circ\text{C}$, boiling point $39\,^\circ\text{C}$, electrical conductivity of solid: poor, liquid: poor, aqueous solution: insoluble
- Bmelting point $-115\,^\circ\text{C}$, boiling point $-85\,^\circ\text{C}$, electrical conductivity of solid: poor, liquid: poor, aqueous solution: good
- Cmelting point $993\,^\circ\text{C}$, boiling point $1695\,^\circ\text{C}$, electrical conductivity of solid: poor, liquid: good, aqueous solution: good
- Dmelting point $1610\,^\circ\text{C}$, boiling point $2230\,^\circ\text{C}$, electrical conductivity of solid: poor, liquid: poor, aqueous solution: insoluble