Synchronization: a. Give an example of a situation in which mutual exclusion is needed. (5pts) b. In the case of single-processor manchine, choose a locking mechanism (between spinlocks, mutex locks, semaphores, and condition variables) to resolve the problem in your example. Why does your choice better suit for the problem? (10pts) c. In the case of multi-processor machine, choose a locking mechanism (between spinlocks, mutex locks, semaphores, and condition variables) to resolve the problem in your example. Why does your choice better suit for the problem?