What is the time complexity of the following implementation of linear search on a linked list?

[answerhappygod]

#include<stdio.h>
#include<stdlib.h>
struct Node
{
int val;
struct Node* next;
}*head;
int linear_search(int value)
{
struct Node *temp = head->next;
while(temp != 0)
{
if(temp->val == value)
return 1;
temp = temp->next;
}
return 0;
}
int main()
{
int arr[5] = {1,2,3,4,5};
int n = 5,i;
head = (struct Node*)malloc(sizeof(struct Node));
head->next = 0;
struct Node *temp;
temp = head;
for(i=0; i<n; i++)
{
struct Node *newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->next = 0;
newNode->val = arr;
temp->next = newNode;
temp = temp->next;
}
int ans = linear_search(-1);
if(ans == 1)
printf("Found");
else
printf("Not found");
return 0;
}
a) O(1)
b) O(n)
c) O(n2)
d) O(n3)