Correct Answer - Option 4 : an insulator
Conductor:
A conductor is a material that allows current to flow through it. Conductors have very low resistance. A conductor having a positive temperature coefficient that means an increase in temperature resistance is also increased. Examples, Gold, silver, copper, aluminum, etc.
Insulator:
An insulator is a material that does not allows current to flow through it and having very high resistance. Insulator has a negative temperature coefficient that means the temperature is increased resistance is decreased. Examples of insulators are Rubber, glass, wood, plastic, porcelain, Polystyrene, paper, etc.
Semiconductor:
A semiconductor is a material whose conductivity lies between conductor and insulator. It is having a negative temperature coefficient that means an increase in temperature decrease the resistance. Examples are Silicon, Germanium, Selenium, Antimoney, etc.
