Correct Answer - Option 4 : All of these
Concept:
Operating system provides an interface between user and computer hardware. There are many functions which are performed by operating system.
Functions:
1. It allows disk access and provides network security.
2. Helps in program execution
3. it handles the i/o operations.
4. Manages the memory and virtual storage.
5. Helps in error detection and handling of errors.
6. It allocates the resources to the system.
7. Provides features such as device management, file management, memory management etc.
8. It provides multi programming in which more than one program can be executed concurrently.