Secondly, the so-called laser is actually the light generated and amplified in the process of stimulated radiation.

Seeing this, you will definitely ask what stimulated radiation is.

Actually, I don't quite understand it either. I'll copy a paragraph for you.

When the photon with frequency =(E2-E 1)/h is incident, it will also cause the particle to quickly jump from E2 level to E1level with a certain probability, and radiate a photon with the same frequency, phase, polarization and propagation direction as the alien photon. This process is called stimulated radiation.

It doesn't matter if you don't understand. I wrote it down just to let you know that lasers are rare and it is a waste to transmit information.

And electromagnetic wave is a very broad concept, as long as you know that light is electromagnetic wave, nothing more.

Do you know optical fiber? The function of silicon dioxide is to transmit information through light.

In reality, optical cables also transmit light, so choose B.