Consider the C code fragment given below. typedef struct node {int data; node* next;} node;void join (node* m, node* n) {node* p = n;while (p- >next! = NULL) {p = p - > next;}p - > next = m;}Assuming that m and n point to valid NULL-terminated linked lists, invocation of join will

• A. append list m to the end of list n for all inputs
• B. either cause a null pointer dereference or append list m to the end of list n
• C. cause a null pointer dereference for all inputs.
• D. append list n to the end of list m for all inputs