A computer cannot perform any function without:

The correct answer is program.

Key Points

• a program is a specific set of ordered operations for a computer to perform. In the modern computer that John von Neumann outlined in 1945,
• the program contains a one-at-a-time sequence of instructions that the computer follows. Typically, the program is put into a storage area accessible to the computer.
• A computer program in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions.
• Therefore, source code may be translated to machine instructions using the language's compiler. (Machine language programs are translated using an assembler) The resulting file is called an executable. 

Additional Information

• Input device: An input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. 
• Hardware: Computer hardware includes the physical parts of a computer, such as the case, central processing unit (CPU), random access memory (RAM), monitor, mouse, keyboard, computer data storage, graphics card, sound card, speakers and motherboard.
• Chip set: The chipset is basically the electronics on the motherboard that communicate with all the connected components.