Twisted-pair cables transmit signals in the form of:

Twisted-pair cables consist of pairs of copper wires twisted together to reduce electromagnetic interference. These cables transmit data signals in the form of electrical currents flowing through the copper conductors. When a device sends information, it converts digital data into varying electrical voltages that travel along the wires to the receiving end. This distinguishes twisted-pair cables from fiber optic cables, which use light pulses (Options A and D), or wireless systems that transmit radio waves (Option C). Since twisted-pair cables rely on copper wiring rather than optical fibers or air-based transmission, the correct answer is Option B (Electric current). Understanding this fundamental difference helps identify appropriate cabling for various networking scenarios, as electrical transmission requires physical copper connections while light-based or wireless methods offer different performance characteristics.