Two identical wires are both carrying the same amount of current flowing in opposite directions. when these wires are brought close to each other they will

Okay so an electric current creates a magnetic field, yeah? So let's see what happens if they'removing in the same direction, as an example. If electrons in both wires are moving in the same direction, they're gonna see the same number of electrons in the other wire (since they are moving at the same speed.) But the thing is, they see more protons, which makes the difference in electric charges attract each other. That makes sense, yeah? So the opposite is gonna happen if they're moving in opposite directions. If they're moving in opposite directions, the electrons are gonna see the high density of electrons in the other wire. (due to relativistic length contraction.) This is gonna cause the wires to move in opposite directions.

the real answer is b. scintillation counter