Which of the following should be used for freeing the memory allocated in the following C code?#include <stdio.h> struct p { struct p *next; int n; }; int main() { struct p *ptr1 = (struct ptr*)malloc(sizeof(struct p)); ptr1->n = 1; ptr1->next = (struct ptr*)malloc(sizeof(struct p)); return 0; }

• A. free(ptr1);
• B. All of above
• C. None of these