class Circle $\{\}$;

class Cylinder extends Circle $\{\}$;

class Cone extends Circle $\{\}$

Cylinder cy $=$ new Cylinder $()$;

Cone co $=$ new Cone $()$;

Circle c$2$;

Cylinder cy$2$;

Cylinder cy$3$;

c$2=$ co; $//$line $1$

cy$2=$ c$2$; $//$line $2$

cy$2=($Cylinder$)$ c$2$; $//$line $3$

Study the whole code above and determine which of $.$ the following statements is true about the three lines above.