The following is a Turing machine that adds 2 to a natural number represented as a binary string. The tape head is pointing to the right most digit of the input number at the beginning. The tape head points to the left most digit of the output number when the computation finishes. 0 is the start state. Find out what is the missing instruction. (0, 0, 0, L, 1) (0, 1, 1, L, 1) (1, , 1, S, halt) (1, 0, 1, S, halt) ____________ A. (1, 1, 0, L, 1). B. (1, 1, 0, L, 0) C. (1, 1, 0, S, halt) D. (1, 1, 1, S, halt)