Concept:A computer needs both physical parts and controlling instructions.
The set of instructions that controls its operation is known as software.
Explanation:Hardware refers to the physical components, such as the monitor and keyboard.
Software is a collection of programs, instructions, and data that tells the hardware what to do.
It includes operating systems, applications, and utility programs.
Without software, hardware cannot perform useful tasks on its own.
Therefore, the phrase "instrument or programs which controls the operation of a computer" describes software.
Answer:A. software