class rectangleType $\{$ public: void setLengthWidth$($double x$,$ double y$)$; $//$Postcondition: length $=$ x; width $=$ y; void print$()$ const; $//$Output length and width; double area$()$; $//$Calculate and return the area of the rectangle; double perimeter$()$; $//$Calculate and return the parameter; rectangleType$()$; $//$Postcondition: length $=0$; width $=0$; rectangleType$($double x$,$ double y$)$; $//$Postcondition: length $=$ x; width $=$ y; private: double length; double width; $\}$; Consider the above class definition, then this variable declaration is correct: rectangle rectangleType; class rectangleType rectangle; rectangle rectangleType.area; rectangleType rectangle;