Answer:
d. x = 5
Explanation:
The standard form of an linear equation: y = mx + 5
Given the equation: y = 5
The above equation has a graph as a horizontal straight line with will intersect with y-xis as point (0,5) with it's slope equals 0
So the equation of a line perpendicular to the line represented by this equation must has a graph as a vertical straight line with the slope equals 0
In 4 answers, only d. x = 5 fit the requirement because it's slope is 0 and it has a graph as a vertical straight line