Correct Option: A

On the basis of the given all information in above question , we can say that
10 cubes are visible and 10 cubes are hidden.
Clearly, there is one column having four cubes.
There are two columns each having three cubes.
There are three columns, each having two cubes.
There are four columns, each having only one cube.
Thus, total number of cubes = 4 + 6 + 6 + 4 = 20 cubes