What are the most common types of metal coils transported?

The most common types of metal coils transported include aluminum, steel, copper, and various specialty alloys due to their widespread use in construction, manufacturing, and various industries. Aluminum is lightweight yet strong, making it ideal for aerospace and automotive applications. Steel is a fundamental material in construction and infrastructure. Copper is highly valued for its electrical conductivity, finding extensive use in electrical wiring and components. Specialty alloys, which can include combinations of metals designed for specific properties, are critical in advanced applications, including aerospace and high-performance engineering.

The other choices include materials that are not typically classified as metal coils. For instance, plastic, rubber, glass, and fabric are non-metal materials and are instead associated with different forms of transportation and handling. Similarly, wood, stone, paper, and concrete do not fall within the category of metal coils and serve other industrial and commercial purposes. Lastly, limiting the options to only aluminum and copper overlooks the significant presence and utility of steel and various alloys in the market. Thus, the comprehensive inclusion of metals in the first choice accurately reflects the primary types transported in the industry.