4. (5 points) Consider the following skeletal C++ program: void fun1(void) { int *pf = new int[10]; //pf is a reference to a dynamically allocated integer array } void fun2(void) { int b; } void main() { int a; //pm is a reference to a dynamically allocated double array double *pm = new double [5]; fun1(); delete []pm; fun2(); //delete the array referenced by pm } (a) what is the lifetime of variable a, b, pm and pf respectively? (b) what is the lifetime of the double array allocated in main(), and integer array allocated in fun1() respectively