Respuesta :
Code segments are extractions from a more complete program.
The code that completes the program is (4) Motion
How to complete the code
From the question, we understand that the program responds when the mouse is moved over a message box.
This means that, the message box reacts to mouse movement or motion on it.
Hence, the code that completes the program is (4) Motion
Read more about code segments at:
https://brainly.com/question/22654163