Quadrilaterals, trapezoids, and parallelograms each have $$4$$ sides each, so the total number of sides is $$4+4+4=12$$. 
When I add together the number of sides of a quadrilateral, a trapezoid, and a parallelogram, I get a total of． 
* $$12$$ 
* $$13$$ 
* $$14$$ 
* $$15$$ 