What is the output of the following code?

#include<stdio.h>
#include<stdlib.h>
struct Node
{
      int val;
      struct Node *next;
}*head;
int get_len()
{
      struct Node *temp = head->next;
      int len = 0;
      while(temp != 0)
      {
          len++;
          temp = temp->next;
      }
      return len;
}
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;
      int len = get_len();
      printf("%d",len);
      return 0;
}

A. 0

B. Garbage value

C. Compile time error

D. Runtime error

Answer: Option A