Q65

The semaphore variables full, empty and mutex are initialized to $0$, $n$ and $1$, respectively. Process P1 repeatedly adds one item at a time to a buffer of size $n$, and process P2 repeatedly removes one item at a time from the same buffer using the programs given below. In the programs, $K$, $L$, $M$ and $N$ are unspecified statements. $P_1$ while (1) { K; P(mutex); Add an item to the buffer; V(mutex); L; } $P_2$ while (1) { M; P(mutex); Remove an item from the buffer; V(mutex); N; } The statements $K$, $L$, $M$ and $N$ are respectively