The Central Processing Unit (CPU) of a computer contains several key components, one of which is the Arithmetic and Logical Unit (ALU). The ALU is responsible for performing calculations and logical operations on data.

Understanding the Role of the Arithmetic and Logical Unit (ALU)

Let's examine each statement provided to determine if it accurately describes a function of the Arithmetic and Logical Unit (ALU):

• I. Performs arithmetic operations: This statement is correct. The ALU is specifically designed to carry out arithmetic computations such as addition, subtraction, multiplication, and division. These operations are fundamental to almost all computations a computer performs.
• II. Store data: This statement is incorrect. While the ALU processes data, it does not primarily store data. Data storage is the function of memory units, such as registers (which provide temporary storage directly accessible to the ALU) or the computer's main memory (RAM). The ALU fetches data from memory or registers and stores the results back to memory or registers after computation.
• III. Perform comparisons: This statement is correct. The ALU performs logical operations, which include comparisons. It can compare two data values to determine if one is equal to, not equal to, greater than, less than, greater than or equal to, or less than or equal to the other. These comparisons are crucial for controlling program flow based on conditions.
• IV. Communicate with input devices: This statement is incorrect. Communication with external devices like input devices (keyboards, mice, etc.) and output devices is handled by I/O controllers or interfaces, which manage the data flow between the CPU, memory, and peripherals. The ALU's role is computation, not direct communication with I/O devices.

Concluding Correct ALU Functions

Based on the analysis of each statement:

• Statement I correctly identifies that the ALU performs arithmetic operations.
• Statement II incorrectly states that the ALU stores data; this is a memory function.
• Statement III correctly identifies that the ALU performs comparisons, which are logical operations.
• Statement IV incorrectly states that the ALU communicates with input devices; this is an I/O function.

Therefore, the core functions of the Arithmetic and Logical Unit among the given options are performing arithmetic operations (I) and performing comparisons (III).