Final answer:
The third control problem in the context of competing processes that must be faced, in addition to mutual exclusion and deadlock, is starvation. Starvation happens when a process consistently cannot access the resources it needs due to other processes being prioritized. Correct option is A.
Step-by-step explanation:
In the case of competing processes, three control problems must be faced: mutual exclusion, deadlock, and starvation. Starvation occurs when a process is perpetually denied necessary resources to proceed with its task, usually because the resource allocation system continually favors other processes.
This is distinct from deadlock, which is a situation where two or more processes are unable to proceed because each is waiting for the other to release resources. On the other hand, mutual exclusion ensures that when one process is using a shared resource, others are excluded from doing the same simultaneously.
Options B) Race Condition and D) Livelock are different issues: a race condition happens when the system's substantive behavior is dependent on the sequence or timing of other uncontrollable events, and livelock is a situation similar to deadlock, where two or more processes continually repeat the same interaction in response to changes in the other's state without doing any useful work.