Which materials are least likely to generate static electricity when rubbed?

Metals are known to be good conductors of electricity and tend to allow electric charges to flow through them easily. When different materials are rubbed together, static electricity can build up in insulators, which are materials that do not conduct electricity well. In contrast, metals do not retain static charges; instead, they dissipate the charge quickly because free electrons can move throughout the entire material.

When it comes to the other materials listed, they can generate static electricity when rubbed together. Wood, depending on its dryness and type, can hold static charge because it is a poor conductor. Rubbed plastic surfaces, being insulators, are famous for generating static electricity, especially after being rubbed or in contact with other surfaces. Glass can also accumulate static charges under certain conditions when rubbed with other materials.

Thus, metals are the least likely to generate static electricity when rubbed, making them the correct choice in this context.