I believe it’s D but I’m not really sure hope this help a little
20X0.3= 6
30X0.3= 9
40X0.3= 12
Check the picture below.
the volume of a rectangular prism is just the product of its 3 dimensions, so the volume of those two there is 4*9*6 and 3*6*5.
so the volume for the composite figure is just the sum of those two products.
If they have -8 points and +6 points, that'd leave them with a total of -2 points.
So the answer is -2.