Answer:
the mouse is an optical mouse
Step-by-step explanation:
The user's mouse does not have a ball to be cleaned when it does not work right because he or she is using an optical mouse. This type of mouse does not use the old-ball-system, but rather uses a light source, which usually consist of a light detector and a light-emitting diode, and this set-up ensures that movement is detected relative to a surface and hence the cursor is moved too.