A is a type of program that runs on an operating system and performs a specific task.

The is responsible for managing input and output (I/O) operations on a computer system.

A is a type of program that allows multiple users to simultaneously access a computer system.

A is a type of software that controls the hardware and software of a computer system and provides a user interface for interaction.

The is responsible for managing the resources (such as CPU time and memory) used by different processes running on a computer system.