The correct answer is option 'C': Register file.

Explanation:
A register file is a collection of general-purpose registers that are combined into a block. These general-purpose registers are used to store temporary data and operands during the execution of a program.

A register file is an important component of a computer's central processing unit (CPU). It provides high-speed storage for data that is actively being used by the CPU. The register file is typically implemented using flip-flops or other types of fast storage elements.

The register file is organized as a set of registers, each with its own unique address. The number of registers in a register file can vary depending on the architecture of the CPU. Common register file sizes include 8, 16, 32, or even 64 registers.

The registers in a register file can be accessed using their addresses. The CPU can read the contents of a register or write new data to a register by specifying the appropriate address. This allows the CPU to quickly retrieve or update the values stored in the registers.

The register file is used for a variety of purposes in a computer system. It is used to store intermediate results during arithmetic and logical operations, to hold function arguments and return values, and to store control information such as program counters and flags.

In addition to the general-purpose registers, some CPUs also have special-purpose registers that serve specific functions. These registers may include program counters, stack pointers, and status registers. These special-purpose registers are typically separate from the register file.

Overall, the register file is an essential component of a CPU, providing fast and efficient storage for temporary data and operands. Its organization and size can vary depending on the CPU architecture, but its purpose remains the same - to store and manipulate data during program execution.