Explanation:

The Central Processing Unit (CPU) is typically composed of the Control Unit (CU), the Arithmetic Logic Unit (ALU), and Registers (internal CPU memory). Option (b) lists "Control unit, ALU, Memory". While 'Memory' (referring to main memory/RAM) is external, in the context of CPU constituents, it often broadly refers to internal memory components like registers and cache, which are integral to the CPU's operation. Options (a), (c), and (d) include external devices like 'Keyboard' or 'Monitor', making them incorrect. Thus, (b) is the best fit among the given choices, interpreting 'Memory' as the CPU's internal memory components.