Choose the graph below that has an undefined slope.

Answer:
The correct option is A.
Step-by-step explanation:
The first line passing through the points (-6,2) and (-6,0).
The slope of a line is
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
The slope of first line is
[tex]m_1=\frac{0-2}{-6-(-6)}=\infty[/tex]
The second line passing through the points (0,-4) and (-1,1). The slope of second line is
[tex]m_2=\frac{1-(-4)}{-1-0}=-5[/tex]
The third line passing through the points (0,-6) and (2,-6). The slope of third line is
[tex]m_3=\frac{-6-(-6)}{2-0}=0[/tex]
The fourth line passing through the points (0,6) and (-3,-7). The slope of fourth line is
[tex]m_4=\frac{-7-6}{-3-0}=\frac{13}{3}[/tex]
Since the slope of a vertical line is infinity, Therefore option A is correct.