Major and if you can, explain how you got your answer

The correct answer is:  [A]:  " 384 in² " .


Explanation:

The formula for the surface area of a cube is:


             →   A   =   6a²  ;
             →   in which:  

                            A  =  surface area of the cube— for which we shall solve ; 
                                               (in "square units" ; or, " in² " ; in our case) ; 

                            a = side length = " 8 in " (given); 
    
   →  Note:  A cube has all equal side lengths.

   →  The "6" in the formula accounts for "6 sides" of a cube.



→  To solve for the surface area of the cube; plug in our known value(s);
                &  solve;  as follows:

                          →  A  =  6 a²  ;

                                    =  6 * (8 in)²  ;

                                    =  6 * 8² * in² ;

                                    =  6 * 8 * 8 * in² ; 

                                    =  48 * 8 * in² ; 

                                    =  384  in²  ;

The answer is:  " 384 in² " ;  

→  which is:  Answer choice:  [A]:  " 384 in² " .