Given the dimensions of locker box are length = 6 feet, width = 4 feet, and height = 10 feet.
Wayne wants to cover the box, so we need to find its total surface area. The box is in the shape of rectangular prism.
We know the formula for total surface area of rectangular prism is given as follows :-
T.S.A. = 2·(6 x 4 + 4 x 10 + 10 x 6) = 2·(24 + 40 + 60) = 2·(124) = 248 feet²
Surface Area = 248 squared feet
To cover the locker with waterproof covering, we needed to find the surface area of the box. As we multiplied two dimensions at a time in the formula, so the units are "squared feet".
Hence, option A is correct i.e. squared feet or ft².