For which scenario would you apply the REPLACE function?

The REPLACE function is specifically designed for substituting specific patterns or substrings within a given text. When working with strings, there are often situations where certain characters or segments need to be changed to meet specific requirements or to clean up data for better processing. For example, if you have a string and want to replace every occurrence of the word "old" with "new", the REPLACE function allows for this transformation efficiently.

In contrast to other functions suggested in the options, the REPLACE function directly focuses on modifying the content of a string rather than summarizing or analyzing its structure, such as extracting parts or measuring length. This makes it the most suitable choice for scenarios where you need to perform text substitutions rather than manipulations like calculating lengths or ensuring formatting. Thus, option B accurately describes the primary use case for the REPLACE function.