(1)The area of the bottom of the box is 4 square feet.

Cube is a 3D object with six squares. Therefore area of the bottom of the box which is a square = 4 Hence each side a=2

Since we know the length of each side we can get the length of the cardboard to make open cubical box with no top.

Sufficient(2)The volume of the box is 8 cubic feet

Volume of cube is a^3=8

Therefore a=2

Same as (1)

SufficientHence answer is D.

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