If you made them redstone, it would make it easier.
If it was redstone (assuming the wires are being powered):
Attach an AND gate to the three incorrect wires. Once on is cut, the output from the AND gate will turn off, so you then attach a NOT gate to the end, so the output would be on. You can attach tnt to the NOT gate's output. With the correct wire, you can attach it to a NOT gate. If it's broken, then the NOT gate's output will turn on.
I want to have four wires (they will be strings) and if you cut the wrong one, you will force everything to explode.
How can I do it?
P.S. You can cut wires only with shears.
If you made them redstone, it would make it easier.
If it was redstone (assuming the wires are being powered):
Attach an AND gate to the three incorrect wires. Once on is cut, the output from the AND gate will turn off, so you then attach a NOT gate to the end, so the output would be on. You can attach tnt to the NOT gate's output. With the correct wire, you can attach it to a NOT gate. If it's broken, then the NOT gate's output will turn on.
Here's the logic gate page on the wiki:
https://minecraft.gamepedia.com/Tutorials/Basic_logic_gates
And here's what it'll look like (I could've made it look simpler, and used less blocks if I knew how to use this tool better.):
(Image from http://mordritch.com/mc_rss/)