9. Consider the following skeletal C program: void funl (void): void fun2 (void): void fun3 (void): void maino ( prototype / prototype/ prototype int a, b, c: void funl (void) ( int b, c, d; void fun2 (void) ( int c, d, e; void fun3 (void) ( int d, e, f: Given the following calling sequences and assuming that dynamic scoping is used, what variables are visible during execution of the last function called? Include with each visible variable the name of the function in which it was defined. main calls funl; funl calls fun2; fun2 calls fun3. 10. Explain dangling problem and lost heap dynamic variables problem. Provide one solution for each