Explanation:

The Central Processing Unit (CPU) is the primary component responsible for executing instructions, performing calculations, and processing data to transform raw 'Input' into meaningful 'Output'. Option (e) 'CPU' is the 'brain' that performs this modification. Option (a) 'Peripherals' are external devices (like keyboards, printers) that provide input or receive output but don't perform the core processing. Option (b) 'Memory' and (c) 'Storage' hold data and instructions, but the CPU actively processes them. Option (d) 'Input output unit' facilitates data transfer, but the CPU does the actual modification.