Which of the following statements are correct in the context of
operating system?

(A) Utility program is the first program loaded into the computer
during booting
(B) Multiprogramming was introduced for interleaved execution
of multiple jobs by the same CPU
(C) DOS is an example of single user operating system.
(D) Mainframe computer uses multiuser operating system.

Choose the correct answer from the options given below:

The correct option is B, C and D Only.

Let us analyze each statement step-by-step to understand why this option is correct:

Statement (A): "Utility program is the first program loaded into the computer during booting"
This statement is incorrect. The first program loaded into the computer's memory during the booting process is the bootstrap loader (typically stored in ROM/BIOS), which then loads the Operating System (OS) kernel into the main memory. Utility programs (such as disk defragmenters or antivirus software) are system software programs that run on top of the operating system and are not the first to be loaded during booting.

Statement (B): "Multiprogramming was introduced for interleaved execution of multiple jobs by the same CPU"
This statement is correct. Multiprogramming is a technique where multiple jobs (or processes) reside in the main memory simultaneously. The single CPU executes these jobs in an interleaved manner. When one job is busy with Input/Output (I/O) operations, the CPU switches to execute another job, thereby maximizing CPU utilization.

Statement (C): "DOS is an example of single user operating system."
This statement is correct. MS-DOS (Disk Operating System) is a classic example of a single-user, single-tasking operating system, designed to allow only one user to execute one command or program at a time.

Statement (D): "Mainframe computer uses multiuser operating system."
This statement is correct. Mainframe computers are high-performance computers designed to handle massive amounts of data processing and support hundreds or thousands of users simultaneously. Therefore, they utilize multi-user operating systems to manage concurrent access and resource allocation.

Since statements (B), (C), and (D) are correct, the correct combination is B, C and D Only.