The first choice of the four graphic options represents the linear function x = 5. (Correct choice: A)
How to determine the representation of a linear function of the form x = a
In this problem we find four choices of graphic representations of linear functions, one of which must chosen based on the following definition of a linear function: x = 5. The graphical representation of a linear function of the x = a is a vertical line passing through point (x, y) = (a, 0), that is, a line parallel with x-axis.
Then, by direct inspection we find that the first choice of the four graphic options represents the linear function x = 5.