Suppose we want to synchronize two concurrent processes P and Q using binary semaphores S and T. The codes for the processes P and Q are shown below. Process P: Process Q: while (1) { while (1) { W: Y: print '0'; print '1'; print '0'; print '1'; X: Z: } } Synchronization statements can be inserted only at points W, X, Y, and Z

Which of the following will ensure that the output string never contains a substring of the form 01n0 or 10n1 where n is odd?