What does concatenation refer to in programming?

Concatenation in programming specifically refers to the operation of linking or combining strings together to form a single string. For instance, if you have two strings, "Hello" and "World", concatenating them would result in "HelloWorld". This operation is fundamental in many programming languages and is often performed using operators like the plus sign (+) or functions like concat().

Other options involve different programming concepts. Reducing file size pertains to data compression techniques, translating code refers to converting source code from one programming language to another (such as from a high-level language to machine code), and debugging a program focuses on identifying and fixing errors in the code. Each of these has its own specific function and does not relate to the process of string concatenation.