Okay kiddo, NTSC-C is a type of TV system that was used in some countries a long time ago.
You know how your TV shows pictures and sounds so you can watch your favorite cartoons? Well, NTSC-C is the way these pictures and sounds are sent over the airwaves to your TV so you can see and hear them.
NTSC-C was used in places like Japan and South America a long time ago when TVs were first invented. But now, most countries use a different TV system called digital television, which is much better and clearer.
Basically, NTSC-C is an old way of sending pictures and sounds to your TV, and we don't really use it anymore.