Most exposure to pesticide concentrates occurs to this part of the applicator's body:

The correct answer highlights that most exposure to pesticide concentrates occurs on the skin, which is the largest organ of the body and often the first point of contact when handling chemicals. Applicators frequently come into direct contact with pesticides when mixing, loading, or applying them, and the skin can absorb these substances, leading to potential health risks.

While hands may receive significant exposure due to direct handling of containers and equipment, and the face could be exposed during application, these are considered more specific areas rather than a broader category. Feet might also be at risk if proper footwear is not used, but overall, the skin is the part of the body that experiences the most widespread exposure due to its entire surface area being potentially in contact with pesticides during application activities.