The line represented by $y=\frac{1}{2} x$ is translated up 4 units. Which option is a graph of the new line?

Step 1 ：Given the line represented by the equation \(y=\frac{1}{2}x\), we need to translate it up by 4 units.

Step 2 ：To translate the line up by 4 units, we need to add 4 to the y-coordinate of the original equation.

Step 3 ：The translated equation is \(y=\frac{1}{2}x + 4\).

Step 4 ：\(\boxed{y=\frac{1}{2}x + 4}\) is the equation of the new line after translating the original line up by 4 units.