Final answer:
Material A with low resistivity is a good conductor (option A), allowing charge to move freely, while material D with high resistivity acts as an insulator, restricting charge movement. Material C, having an intermediate resistivity, is a semiconductor with electrical properties that can be manipulated for use in electronics.
Step-by-step explanation:
The electrical resistivity of a material determines its ability to conduct electric charge. Good conductors have low resistivity, meaning they allow electrical charge to move through them easily, resulting in high conductivity. Materials like copper and silver are often used as conductors due to their low resistivity. On the other hand, insulators are materials with high resistivities, and they do not allow electric charge to flow freely; examples include rubber and glass.
A semiconductor falls between these two extremes, with intermediate resistivity. Silicon is the most commonly used semiconductor in electronics. The resistivity of semiconductors can be altered significantly by adding impurities, a process known as doping, which allows engineers to tailor the electrical properties for various applications in modern electronics.