Source code

Source code refers to the human-readable version of a computer program. It is written in a high-level programming language, which is designed to be easily understood by humans. The source code is essentially a set of instructions that tell the computer what to do. It is the starting point for the development of any software application and serves as a blueprint for the program's behavior.

Understanding the options:

a) Cache: Cache is a component of a computer's memory hierarchy that stores frequently accessed data for faster retrieval. It is not related to the human-readable version of a program.

b) Instruction set: An instruction set is a group of commands and operations that a computer's processor can execute. It defines the operations that can be performed by the processor and their corresponding machine code representations. It is not the human-readable version of a program.

c) Source code: Source code, as mentioned earlier, is the human-readable version of a program. It consists of statements and structures written in a high-level programming language such as Python, Java, C++, etc. Source code is typically written by programmers to create software applications.

d) Word size: Word size refers to the number of bits that a computer processor can handle at once. It determines the maximum amount of data that can be processed in a single operation. Word size is not related to the human-readable version of a program.

Conclusion:

The correct answer to the given question is option 'C' - Source code. It is the human-readable version of a computer program written in a high-level programming language. Source code serves as the foundation for software development and provides instructions for the computer to execute.