Word length of a personal computer is                 .

The correct answer is 64 bits. The word length (or word size) of a computer refers to the maximum number of bits that the CPU can process, store, and transfer in a single operation. It determines the size of general‑purpose registers, integer arithmetic capabilities, and the maximum addressable memory space. While earlier personal computers used smaller word lengths, all modern PCs are built on 64‑bit architecture.

Why 64 Bits Is the Correct Answer

• Modern PC Standard: Since the mid‑2000s, every mainstream personal computer—whether running Windows, macOS, or Linux—has been powered by a 64‑bit processor (x86‑64 architecture from Intel/AMD or ARM64 from Apple Silicon and Qualcomm). This has become the baseline for even entry‑level desktops and laptops.
• Technical Advantages: A 64‑bit word length allows the CPU to handle massive integers (up to 2⁶⁴‑1) and directly address up to 16 exabytes of RAM (though practical motherboard limits are far lower). This far exceeds the 4‑gigabyte ceiling of 32‑bit systems, enabling seamless multitasking and large‑scale data processing.
• Software Requirement: Most modern operating systems and applications are compiled natively for 64‑bit processors. Even budget PCs today ship with 64‑bit processors and run 64‑bit operating systems, making "64 bits" the only accurate representation of a current‑generation personal computer.

Why the Other Options Are Incorrect

• 4 bits (Option 1): This was used in the very first microprocessors (like the Intel 4004, released in 1971), but they were designed for calculators and embedded systems, not personal computers.
• 8 bits (Option 2): Personal computers in the late 1970s and early 1980s (such as the Apple II and Commodore 64) used 8‑bit processors. These are obsolete by today’s standards.
• 16 bits (Option 3): The 16‑bit era included the Intel 80286 and early IBM PC/AT models. These were common in the mid‑1980s but were completely replaced by 32‑bit and later 64‑bit systems.

In summary, while historical PCs used smaller word lengths, the universal standard for personal computers today is 64 bits, making it the definitive answer.