What does a statement in programming do?

A statement in programming is fundamentally a command that instructs the computer to perform a specific action. This understanding aligns most closely with the choice that states a statement executes a specific action one at a time. For example, statements can include expressions, assignments, function calls, or control flow directives, all of which tell the program to perform distinct operations sequentially.

When a program runs, it processes each statement in the order they are written unless directed otherwise by control flow mechanisms. This sequential execution is critical for ensuring that the program performs actions systematically, leading to the desired results.

In contrast, the other choices refer to concepts that do not encapsulate the essence of what a statement does in programming. The overall structure of a program involves multiple components beyond individual statements, such as functions, classes, and modules. Transforming data pertains more to specific functions or operations rather than the general action of a statement. Lastly, the declaration of variables is a different concept that pertains to defining a variable's name and type, which is not the primary function of a statement itself. This distinction reinforces why executing a specific action one at a time is the most appropriate definition of a statement in programming.