The following figure depicts the outline of a large fairy ring that has appeared overnight in an open meadow,as viewed from above.The fairy ring represents the furthest advance of this mycelium through the soil.Locations A-D are all 0.5 metres below the soil surface.Responses may be used once,more than once,or not at all.

-Assume that all four locations are 0.5 m above the surface.On a breezy day with prevailing winds blowing from left to right,where should one expect to find the highest concentration of free basidiospores in an air sample?