Which of the following operations is NOT performed by an ALU ?

The Arithmetic Logic Unit (ALU) is a fundamental digital circuit within the CPU designed specifically to perform arithmetic and logical operations on binary data. Its primary functions include basic mathematical calculations such as addition, subtraction, multiplication, and division, along with logical operations like AND, OR, NOT, and comparisons. Therefore, options A (Addition), B (Subtraction), and C (Multiplication) are all standard operations executed directly by the ALU. String manipulation, however, involves processing sequences of characters and requires complex memory management and specialized instructions that are typically handled by the control unit or specific software routines rather than the core arithmetic logic circuitry. Consequently, string manipulation is NOT a direct operation performed by the ALU itself.