A desktop monitor blanks for a moment whenever its video cable is nudged, and its owner mentions it also blanked once when the desk was bumped. How should this intermittent be classified, and why?

Select one answer.

• Time and environment, because a monitor sits in a room all day, and faults in stationary equipment are always caused by weather, season, and hours of operation rather than by anything that physically moves the equipment or its cabling.
• Thermal, because monitors warm up in use, and any fault in a device that produces heat must be provoked by rising temperature regardless of what the fault's own pattern suggests.
• It cannot be classified, because intermittents are classified by their symptom rather than by their trigger, and a blanking symptom appears identically in every class of intermittent fault.
• Mechanical, because the fault follows motion and impact — a nudged cable and a bumped desk — which points at a tired connector, a solder-fatigued port, or a broken strand making and losing contact, and names flex, tap, and vibration as the provocation to try.