What is a primary purpose of functions in programming?

The primary purpose of functions in programming is to reduce redundancy and improve code organization. Functions allow for the encapsulation of code into reusable blocks that can be invoked multiple times throughout a program without the need to rewrite the same code over and over again. This modular approach not only saves time but also enhances readability and maintainability of the code.

By breaking complex processes into smaller, manageable parts, functions help in organizing the code more logically. Each function can perform a specific task, making it easier to troubleshoot and update parts of the program without affecting the entire codebase. This approach is fundamental in software development as it promotes better collaboration among developers, easier testing of individual components, and overall cleaner code structure.

In contrast, increasing runtime or creating complexity does not align with the efficient use of functions; rather, functions aim to streamline processes. Additionally, while functions may influence how variables are organized, they are not primarily used to limit the number of variables. The focus is instead on improving code reuse and clarity, making option B the correct choice.