Answer: Option - 2) Light
In fiber optic cable, the signal source is light wave.
Explanation: In fiber optic cable the data transmission send information through electronic signal into light wave. When the input data is given in the form of electronic signal, then it gets converted into light signal with the help of light source. As fiber optic is a medium for carrying information in the form of light from one medium to another. Fiber optics are beneficial as it is used in long distance data transmission.
