Which of the following is not a good conductor of electricity?

• A. Saliva
• B. Water
• C. Copper
• D. Gold

Answer: (A)

Conductivity depends on how freely charge carriers can move. Metals like copper and gold have lots of free electrons that can drift quickly, making them excellent conductors. Water conducts when it contains dissolved minerals or salts, because ions carry charge; the more ions and mobility, the better the conduction. Saliva, while it does have electrolytes, isn’t as able to pass charge efficiently due to its composition and viscosity, so it conducts electricity much less well than metals or typical hydrated solutions. That makes saliva not a good conductor of electricity among the given options, even though it can carry some current.