Step 1: Electrical conduction in a liquid needs free ions that can carry charge.
Step 2: Pure water contains very few ions, since it dissociates into \(H^+\) and \(OH^-\) only to a tiny extent. This is why pure, distilled water carries almost no measurable current.
Step 3: Ordinary tap water conducts electricity much better than pure water because it contains dissolved salts and minerals that provide plenty of free ions.
So pure water is correctly described as a bad, or poor, conductor of electricity. The correct answer is option B.