What does string interpolation allow you to do?

String interpolation allows you to inject variable values into a string template. This process involves embedding variables directly within a string literal, making it easy to construct dynamic strings that include the current values of those variables. For instance, in many programming languages, you can define a template string that contains placeholders which are then replaced with actual variable values at runtime. This is particularly useful for generating output that requires variable content, such as combining static text with user-provided information or computed values.

The other options describe useful operations in string manipulation but do not capture the essence of string interpolation specifically. Formatting strings for output typically refers to aligning text, numbers, or dates, whereas combining multiple strings into one is more about concatenation. Defining complex data structures goes beyond the scope of just strings and involves creating and organizing data types like arrays or objects. Each of those operations serves a different purpose but does not fulfill the precise function of string interpolation.