a binary semaphore i. Has only two value for its variable ii. is used to create mutual exclusion situation in process synchronization. iii. does not guarantee only one process can enter critical section iv. is used to create turns for many processes trying to access a resources. Select one: O A i and iv only. O B. i and ii only OC. i, ii and ili only OD. i, ii, iii and iv A spooler 1. mediates between a computer application and a slow peripheral, such as a printer. II. retrieve documents produced by computer from a queue at the speed of the computer, then retrieved and printed at the speed of the printer III. can be used between a computer system and a card reader IV. release user from having to wait for output from a printer to be ready. Select one: O A None of the above. O B. I, II, III and IV only OC I and I only OD. I, II and IV only