Which of the following is a reason to use shielded wire?

Using shielded wire is primarily advantageous for preventing coupling of unwanted signals to or from the wire. Shielded wire incorporates a layer of conductive material, such as foil or braid, surrounding the insulating conductor. This shield acts as a barrier against electromagnetic interference (EMI) and radio frequency interference (RFI), which are common types of noise that can distort signals or cause unwanted crosstalk in communication systems.

When the shield is properly grounded, it effectively reduces the potential for external signals to couple into the wire, ensuring that the signals being transmitted remain clear and unaffected by external influences. This is particularly important in applications involving sensitive electronics or critical communications, where maintaining signal integrity is essential.

Other choices pertain to different properties of wire and do not relate to the primary purpose of shielding. For instance, decreasing resistance or increasing current-carrying capability do not align with the function of shielded wire, nor does coupling signals pertain to the protective aspect of the shielding. Therefore, the use of shielded wire is best justified by its role in minimizing unwanted signal interference.