Let's evaluate the electrical conductivity of each material: (a) Mica: Mica is an excellent electrical insulator. (b) Graphite: Graphite, a form of carbon, is a good electrical conductor due to the delocalized electrons in its layered structure. (c) Sulphur: Sulphur is a non-metal and an electrical insulator. (d) Human body: The human body contains water and ions, which allows it to conduct electricity.