The correct answer is that copper is mainly used for conducting electricity because its electrical resistance is low (option D). Copper has excellent electrical conductivity, second only to silver, but is more affordable, making it the material of choice for most electrical wiring and components. Its low electrical resistance means that electric current can flow through copper with minimal energy loss, ensuring efficient transmission of power. Additionally, copper is highly durable and resistant to corrosion, which further enhances its suitability for long-term use in electrical systems. While factors like its high melting point and relative cost are also considerations, the primary reason for its widespread use in electrical applications is its superior conductivity. This characteristic makes copper essential in a wide range of industries, including power generation, telecommunications, and electronics, where efficient and reliable electrical performance is critical.