In which type of material would you find a full valence band?

A full valence band is characteristic of insulators. In these materials, the valence band is completely filled with electrons, meaning there are no available states for electrons to move into, which results in poor electrical conductivity. This full occupancy of the valence band prevents the electrons from jumping to the conduction band under normal conditions, which is essential for electrical conduction.

Conductors typically have overlapping bands or a partially filled valence band, allowing for easy movement of electrons. P-type and N-type semiconductors have specific doping mechanisms that create holes or additional electrons, respectively, leading to partially filled bands. Therefore, all these options do not have a fully occupied valence band in the same context as insulators do.