The following function reverse() is supposed to reverse a singly linked list. There is one line missing at the end of the function.
```
/* Link list node */
struct node
l
int data:
struct node* next,
$$\$7 $$
/* head_ref is a double pointer which points to head {or start} pointer
of linked list */
static void reverse{struct node** head_ref}
i
struct node* prev = NULL?
struct node* current = *head_reff
struct node* next,
while (current != NULL)
l
next = current->next?
current->next = prevy
prev = current;
current = next;
l
/* predict the statement here */
1
```
What needs to be added instead of "/ $/$ predict the statement here $* / "$, so that the function correctly reverses a linked list.
A. *head_ref=prev;
B. *head_ref = current;
C. *head_ref=next;
D. * head_ref=NULL;