Volume Under Stairs is the Combination of two Different Cuboid
We know, Volume of a Cuboid = l * b * h
Dimensions of Larger Cuboid = 5 * 10 * 7
Dimensions of Smaller Cuboid = 2 * 4 * 10
So, Volume = (5 * 10 * 7) + (2 * 4 * 10)
V = 350 + 80
V = 430 in³
In short, Your Answer would be: Option A
Hope this helps!
