Which of these is NOT a detection countermeasure for mines and booby traps?

Deactivation is the correct answer in this context because it refers to the process of neutralizing a mine or booby trap after it has been detected, rather than a method of detecting them. The key aspect of detection countermeasures is to identify the presence of mines and booby traps before they can cause harm, therefore methods that serve this purpose include mine detectors, visual inspections, and probing.

Mine detectors use electromagnetic fields to locate metal components within mines and explosive devices, while visual inspection involves searching an area for signs of such devices, like disturbed soil or unusual markers. Probing involves physically checking the ground in suspected areas of explosives by using a rod or stick to carefully feel for hidden threats. All of these techniques are focused on detection, setting them apart from deactivation, which comes into play after the device has been located.