Which of the following lines should be inserted to complete the following recursive implementation used to find the length of a linked list?#include#includestruct Node{      int val;      struct Node *next;}*head;int recursive_get_len(struct Node *current_node){      if(current_node == 0)        return 0;      return _____;}int main(){      int arr[10] = {1,2,3,4,5}, n = 5, i;      struct Node *temp, *newNode;      head = (struct Node*)malloc(sizeof(struct Node));      head->next = 0;      temp = head;      for(i=0; ival = arr[i];          newNode->next = 0;          temp->next = newNode;          temp = temp->next;      }      int len = recursive_get_len(head->next);      printf("%d",len);      return 0;}