Sorry, I have a couple more questions.

For this question:

Which one of the following solutions will be the worst electrical conductor at 25 degrees C?

d) 0.10 mol L^(-1) CH3OH (aq)

How would I solve this? the answer was d.

You don't give the other possibilities but the way you work the problem is to look for the material that has the least number of ions. CH3OH is a covalent compound and doesn't ionize at all. No ions means no electrical current. Some of the other possible answers probably are insoluble and others are soluble and produce ions.