This question has to do with the change in the subject of the formula.
So we will proceed thus:
[tex]\begin{gathered} 4x-2y=8 \\ \text{Making y the subject of formula will give:} \\ \end{gathered}[/tex][tex]\begin{gathered} 4x-8=2y \\ \text{Divide both sides by 2} \\ \frac{4x-8}{2}=\frac{2y}{2} \\ 2x-4=y \end{gathered}[/tex]The correct answer, therefore, is the third option:
[tex]y=2x-4[/tex]