The statement in option D is TRUE.
From the graph, you can see that one eraser cost 50 cent and all the eraser cost the same. Following the graph, you will observe that, when the total cost of the eraser is $3.5 on the vertical axis, the corresponding point on the horizontal axis is 7.
That particular plot on the graph is telling you that when seven erasers are bought, the total cost is $3.5.
Plug 
into the equation of the ellipsoid:
Complete the square:
Then the intersection is such that
which resembles the equation of a circle, and suggests a parameterization is polar-like coordinates. Let
(Attached is a plot of the two surfaces and the intersection; red for the positive root 
, blue for the negative)
Forty Thousand - Word Form
40,000 - Number Form
Replace x in the equation with the x values in the table and solve for y.
-8(5/2)^-3 = -64/125
-8(5/2)^-1 = -16/5
-8(5/2)^0 = -8
-8(5/2)^2 = -40
