Steel spoon, metal clip, and copper wire all or made of metal while the plastic clip is a non-metal thing. And we know that only metals conduct electricity that's why they are conductors and non-metals do not conduct electricity that is why they are insulators. Hence, conductors allow the current to flow that is why option (a),(b) and (d) are not right option and only (c) is the correct option which does not allow current to flow and will not let the bulb glow.

The key difference between conductors and insulator is that conductor conduct electricity while insulators do not.