The incorrect answer is B.
All you have to do is plug in x to the formulas and see if the are equal.
4x - 2 = 3x + 6
4(8) - 2 = 3(8) + 6
30 = 30
CORRECT
The second is not only not equal, but it is the wrong kind of formula for what you are trying to prove there.
Hope that helps!