The correct answer is: C. Single user, multitask
A PDA (Personal Digital Assistant) is a small, handheld computer that is typically used for tasks such as scheduling appointments, managing contacts, and taking notes. PDAs typically run on a single-user, multitasking operating system. This means that only one person can use the PDA at a time, but it can run multiple programs at the same time.
A real-time operating system (RTOS) is an operating system that guarantees a certain level of response time to external events. This is important for applications such as controlling industrial machinery or monitoring medical equipment, where a delay in response could have serious consequences.
A single-user, single-task operating system is an operating system that can only be used by one person at a time and can only run one program at a time. This type of operating system is typically used on small, embedded devices such as calculators and microwave ovens.
A multiuser, multitask operating system is an operating system that can be used by multiple people at the same time and can run multiple programs at the same time. This type of operating system is typically used on desktop computers and servers.