Final answer:
ATMs are classified as Soft real-time systems because they require timely transaction processing with some leniency for minor delays, unlike Hard real-time systems that cannot tolerate any delay.
Step-by-step explanation:
Automated Teller Machines (ATMs) belong to the category of Soft real-time systems. These systems are designed to handle operations that are time-sensitive, but not to the extent where failure to meet exact timing constraints would result in a total system failure. In the context of ATMs, they need to process transactions in a timely fashion to ensure customer satisfaction, but a small delay typically does not have catastrophic consequences, unlike in Hard real-time systems where a delay could lead to severe damages or risks to life.
Even though ATMs require a certain level of time sensitivity, such as in updating account balances to prevent overdrafts or fraud, they can tolerate minor delays, hence, they do not fit into the Hard real-time systems category. They are more lenient than systems that control life-critical applications, such as those found in avionics or medical devices. Therefore, the correct answer is B. Soft real-time systems.