Final answer:
Lasers are the primary electro-optical components used in light sources for testing multimode Local Area Networks due to their efficient transmission of light with low loss, high bandwidth, and reduced crosstalk.
Step-by-step explanation:
Light sources used to test multimode Local Area Networks (LANs) typically use an electro-optical component known as a laser. Optical fiber cables favor lasers over other light sources due to their ability to travel long distances with low loss, high bandwidth, and reduced crosstalk. These qualities of laser light are central to their use in fiber optics, where the principle of total internal reflection is applied to transmit light efficiently through fibers. In testing multimode LANs, lasers provide accurate and reliable means to assess the integrity and performance of the optical network.