Question

The figure shows a line graph and two shaded triangles that are similar:

Answer 1

We know that
the equation for calculating the slope of a line is
m=(y2-y1)/(x2-x1)

look for any two points on the graph
let
A(0,0)
B(3,1)
m=(1-0)/(3-0)------> m=1/3

the slope  is 1/3 throughout the line

therefore 
the answer is the option
B-It is 1/3 throughout the line