Which of the following examples is a poor conductor of electricity? 

Normal conductors of heat and electricity are metals, whereas insulators are nonmetals. Conductivity is the quality of conductors that enables them to conduct electricity. Electric current is the movement of electrons across a conductor, while voltage is the amount of force needed to cause that movement.

Because there are free-moving electrons present, metals conduct electricity. As a result, the electrons are less resistant to current flow. Silver and copper are the top electrical conductors. Additionally, the nucleus's attraction to the valence electrons in metals is minimal. As a result, these electrons have unrestricted movement. Non-metals lack the necessary density and free electron supply to properly conduct electricity. Electrons are securely contained and prevented from freely moving in non-metals. They act poorly as a result.

Being a non-metal, oxygen lacks the necessary free electrons to conduct electricity. These electrons are restrained and prevented from moving freely.

So, the correct answer is Option A.