Hi there! The answer is C.
We can find the slope of this line by making y the subject of the equation.
[tex]3x - 4y = 8 \\ - 4y = - 3x + 8 \\ y = \frac{ - 3}{ - 4} x + \frac{8}{ - 4} \\ y = \frac{3}{4} x - 2[/tex]
Now we can see that the slope of this line (which is positioned in front of x) is 3/4. Therefore, the slope of any line parallel to this one is 3/4 as well. The answer is C.