This question is about race conditions and mutual exclusion. Which of the following statements are true? Select one or more: a. Mutual exclusion should be used even when only one process accesses a particular resource. b. Mutual exclusion should not be enforced in non-critical regions. M C. A program can only have one critical region. Ud. Race conditions can be avoided by using a mutual exclusion mechanism. e. Critical regions consist of code that should never be executed.