Answer:
C. parallel lines
Explanation:
If two straight lines be at right angles to the same plane, the straight lines would be parallel.
The slope is going to be negative. Pick any two points from the graph and find the slope.
m= -3
pick any point on the line, I picked (0,4) and find "b"
y=mx+b
4=(-3)(0) +b
b= 4
y=-3x + 4
C is the right answer
Hope this helped