Answer:

Step-by-step explanation:
We have to keep in mind that a good conductor would be a substance that has the ability to produce ions (charged species). These species are responsible for the electricity conduction on water.
Therefore, we have to check which ones of these compounds will produce ions in water. For
and
we have diatomic molecules (also gases) this type of molecules don't have the ability to produce ions due to his simplicity, they already are very stable.
In the sugar molecule
we have a covalent compound. The ions are produced by ionic compounds. So, this molecule can be discarded too.
For
we have an ionic compound that have the ability to produce ions:

So, this is the compound that would be a good conductor due to the
and the
ions.