Final answer:
The wind condition that poses the highest risk for wake turbulence during landing is a light, quartering tailwind. This type of wind makes it harder to avoid the turbulent air from preceding aircraft, and it can cause wake to linger on the runway.
Step-by-step explanation:
The wind condition that requires maximum caution when avoiding wake turbulence on landing is a light, quartering tailwind. This type of wind can make it more difficult for a plane to maintain separation from the turbulent wake of a preceding aircraft. With a quartering tailwind, the turbulent air pushed behind by the leading aircraft may stay on the runway longer and not be carried away as quickly as with a headwind. Additionally, the light nature of the wind can lead to less predictable movement of the turbulence.
Airplanes typically take off into the wind to reduce the ground speed required for takeoff. This is because the airspeed - the speed of the aircraft relative to the surrounding air mass - is of utmost importance for lift. When an aircraft is facing a headwind, it achieves higher airspeed at a lower ground speed, which is preferable for both takeoff and landing.