Final answer:
A. User-defined Functions, C. Inline Functions, and B. Recursive Functions are types of functions that can promote code re-use and reduce query complexity.
Step-by-step explanation:
User-defined Functions are used to promote code re-use and reduce query complexity. These functions allow you to define and use your own custom functions to perform specific tasks. They can be called multiple times from different parts of the code, eliminating the need to write the same code repeatedly.
Inline Functions are another type of function that promotes code re-use and reduces query complexity. They are small functions defined within the scope of another function, and are typically used when the same task needs to be performed multiple times within that function.
On the other hand, Recursive Functions can also promote code re-use, but they can lead to increased query complexity. Recursive functions call themselves repeatedly until a certain condition is met. While effective for certain problems, they may introduce additional overhead and complexity.