Answer:
A.
Explanation:
The formula for the volume of a rectangular prism is V=lwh.
You know all three of those. If the base area is 40 sqft, you can assume that the width is 10, and the length is 40, or any other two numbers that equal 40. So, you can just keep 40 as both your length and width since l x w is the area.
So now you have 40x6, aka the height of your rectangular prism.
Therefore, V= 40 x 6.