Diego is building a kitchen table and a coffee table. The legs of a kitchen table must be twice the height of a coffee table, and there are 4 legs on each table. He writes the expression 4(2x) + 4(x) to model his building plans. What does the entire expression represent?

The sum of the heights of all kitchen table legs
The sum of the heights of all coffee table legs
The sum of the heights of all table legs
The sum of the heights of all kitchen and coffee tables