According to the graph what is the value of the constant in the equation below

As you can see in the picture, all the points lie on the same line, so they are collinear. The line follows an equation with the general form of:

y = mx + b
where m and b are the constants

The b parameter is the y-intercept. This is the point at which the line intersects the y-axis. From the graph, b = 0. The other constant is the slope m. You can choose any two points, the answer would just be the same.

m = (y₂ - y₁)/(x₂ - x₁)
Suppose point 1 is (2,1) and point 2 is (3,1.5).

m = (1.5 - 1)/(3 - 2) = 1/2 or 0.5

Therefore, the answer is either 0 or 0.5. From the choices, the answer would be letter C.