Which of the following are typical core functions provided by an operating system?

Introduction / Context:
An operating system (OS) is the main system software that manages hardware resources and provides services for application programs. Modern operating systems do far more than show a desktop; they schedule processes, manage memory, and coordinate input/output operations. This question asks you to identify which listed activities are standard responsibilities of an operating system.

Given Data / Assumptions:

• The system discussed is a general purpose operating system such as Windows, Linux, or macOS.
• The options list multiprogramming, input/output control, and virtual storage.
• We assume a textbook level understanding of OS design.
• We must decide whether one, some, or all of these are standard OS functions.

Concept / Approach:
At its core, an operating system manages processes, memory, and I/O devices. Multiprogramming allows more than one process to reside in main memory and share CPU time, improving utilisation. Input/output control covers device drivers, buffering, and access to files and peripherals. Virtual storage, often called virtual memory, allows the OS to extend the apparent memory available to programs by using disk space. Because all three listed items fall within typical OS responsibilities, the best answer is the combined option that states All of the above functions.

Step-by-Step Solution:
Step 1: Recognise multiprogramming as a scheduling and memory management technique handled by the OS. Step 2: Identify input/output control as the OS role in coordinating disks, keyboards, screens, printers, and other devices. Step 3: Understand virtual storage as the OS feature that maps logical addresses to physical memory and disk, enabling larger apparent memory. Step 4: Observe that all three tasks require privileged access to hardware and system wide coordination, which is the operating system's domain. Step 5: Select the option stating that all the listed functions belong to the operating system.

Verification / Alternative check:
Operating system textbooks describe key services including process management (which implements multiprogramming), memory management (which includes virtual memory), and device management (which includes I/O control). These components are part of standard OS kernels such as Linux or Windows NT. Application programs rely on system calls to request these services; they do not implement them directly. This confirms that all the mentioned items are indeed OS functions.

Why Other Options Are Wrong:
Multiprogramming to run several jobs apparently at once: Correct but incomplete, as it omits other OS services. Input/output control for devices and files: Correct but incomplete in the same way. Virtual storage or virtual memory management: Also correct but not the only OS role discussed.

Common Pitfalls:
Students sometimes associate operating systems only with graphical interfaces and forget the deeper resource management tasks. Another pitfall is to treat each option as a separate candidate without noticing that they all describe genuine OS responsibilities. In many multiple choice questions, when several individual statements are correct, the intended answer is the option that combines them, such as All of the above functions.

Final Answer:
All three listed activities are operating system responsibilities, so the correct choice is All of the above functions.