What do conditional statements allow programmers to do?

Conditional statements are crucial in programming as they enable the execution of code based on specific conditions. This means that a programmer can write instructions that only run when certain criteria are met, allowing for dynamic decision-making in code. For example, if a condition evaluates to true, a particular block of code will execute; if it evaluates to false, that code block is skipped. This functionality is essential for creating interactive and responsive applications, allowing the program to adapt its behavior based on the user's input or other changing data.

The other options pertain to different programming concepts: repeating code relates to loops, storing data involves variables, and defining new functions refers to creating reusable code blocks. These concepts are important in their own right but do not specifically encapsulate the purpose and functionality of conditional statements.