Which of the following may not be used in damp or wet locations?

Type NM nonmetallic cable is not suitable for use in damp or wet locations due to its design and materials. This type of cable is intended primarily for residential indoor applications, where it can be kept dry. It features a nonmetallic jacket that is not water-resistant, which makes it vulnerable to moisture and can lead to deterioration, therefore increasing the risk of electrical hazards such as short circuits or electrical shocks.

On the other hand, Type AC armored cable, Type UF underground feeder cable, and EMT conduit are all designed with materials that provide better protection against moisture and damp conditions. Type AC cable is equipped with an internal metal armor that offers some moisture resistance, making it acceptable for use in certain damp environments. Similarly, Type UF cable is specifically designed for direct burial and can handle exposure to wet conditions. EMT conduit is often used to protect cables in wet locations, as it is a rigid metal conduit that can shield against moisture while providing physical protection.