If a line is vertical then it has an undefined slope.If a line has an undefined slope, then it is a vertical line.✔ If a line is not vertical then it does not have an undefined slope.If a line does not have an undefined slope, then it is not a vertical line.
Answer
A
If a line is vertical then it has an undefined slope.
B
If a line has an undefined slope, then it is a vertical line.
C
✔ If a line is not vertical then it does not have an undefined slope.
D
If a line does not have an undefined slope, then it is not a vertical line.