Explanation:

The 'box' that contains the central electronic components of the computer refers to the physical enclosure that houses all the internal hardware. This enclosure is known as the system unit. It contains the motherboard, CPU, RAM, power supply, and other internal drives. Option (a) 'motherboard' is a circuit board *inside* the system unit where many components are mounted, but it is not the 'box' itself. Option (c) 'peripheral' refers to external devices connected to the computer, not the main housing. Option (d) 'input device' refers to components like keyboards or mice, which are also external or connect to the system unit. Therefore, the 'system unit' (b) is the correct term for the physical box containing these central components. Option (e) 'none of these' is incorrect as (b) is the accurate answer.