Which method is used to perform high-speed data transfer over copper wires?

DSL, or Digital Subscriber Line, is designed specifically for high-speed data transfer over traditional copper telephone wires. It allows for simultaneous voice and internet communication by utilizing different frequency ranges, which separates voice traffic from data traffic. This technology enables faster internet speeds compared to older methods such as dial-up, which operates over standard phone lines but does not support high-speed data transfer.

The MAX function is a programming or computational concept that does not pertain to data transfer methods. COBOL is a programming language used primarily in business environments, which is unrelated to the transfer of data over physical mediums. Therefore, DSL stands out as the appropriate choice for effective high-speed data transmission over copper infrastructure.