It shall be the letter ........b
A cube has six sides so you divide 3750 by 6 to find the area of a single face. This would be 625. Area is length times width and since it is a cube you know that both are the same. This gives you an answer of 25.
Let's calculate the actual area: it is 11*5.6*7.2 or 443.52 cubic meters. Is the 100+ cubic meters error reasonable? :)
