The electrical conductivities of two compounds, Y and Z, are listed below. For Y: the compound has good conductivity when in the liquid state; the mixture formed after adding the compound to water also has good conductivity. For Z: the compound does not conduct in the liquid state; the mixture formed after adding the compound to water has good conductivity. What are compounds Y and Z?
- AY: $\text{Al}_2\text{O}_3$, Z: $\text{SiCl}_4$
- BY: $\text{NaCl}$, Z: $\text{Al}_2\text{O}_3$
- CY: $\text{NaCl}$, Z: $\text{SiCl}_4$
- DY: $\text{SiCl}_4$, Z: $\text{Al}_2\text{O}_3$