While debugging an ABAP program, how can you make the program stop whenever the value of a variable changes?

The best choice for stopping an ABAP program whenever the value of a variable changes is the watchpoint. A watchpoint is specifically designed to monitor a variable for changes, allowing the debugger to halt execution when the specified condition is met—such as when the variable's value is modified. This feature is particularly useful for tracking down bugs related to unexpected changes in variable values during the execution of the program.

In contrast, exception breakpoints are triggered when a runtime error occurs, not when a variable's value changes. Conditional breakpoints, while they allow for halting execution based on specific conditions, are not specifically intended for monitoring value changes of a variable in a straightforward manner. Programmatic breakpoints are placed directly within the source code by inserting the BREAK statement, which does not relate to monitoring changes in variable values dynamically. Thus, the watchpoint effectively serves the purpose of stopping the program precisely when a variable changes, making it the correct choice.