Which statement best describes an IF statement?

The best description of an IF statement is that it allows branching in the program. An IF statement is used to make decisions within a program. It evaluates a condition and executes a block of code only if that condition is true, effectively creating a branch in the flow of the program. This means that different paths can be taken depending on whether certain criteria are met, enabling more dynamic and responsive programs.

In contrast, repeating a block of code relates to loops, which are not the function of an IF statement. Combining multiple codes typically refers to concepts such as functions or methods where code can be grouped and reused, rather than decision-making structures. Defining a function involves specifying a reusable block of code that can be executed when called, which is a different concept altogether from the decision-making aspect of an IF statement.