Which formulation type requires that herbicide be suspended in water prior to application?

The formulation type that requires the herbicide to be suspended in water prior to application includes all of the choices provided.

Soluble concentrates are designed to dissolve completely in water, allowing them to be mixed into a solution that can be easily applied. This means that before application, the herbicide must indeed be suspended in water to ensure it is uniformly distributed.

Flowables also require mixing with water. They contain solids suspended in a liquid, those solids need to be evenly dispersed in the liquid before application. This ensures that the flowable formulation delivers the active ingredient uniformly across the target area.

Wettable powders are solid formulations that do not dissolve in water but require agitation to ensure they form a suspension. When mixed with water, they can be effectively applied as they need to be suspended rather than dissolved.

In summary, each formulation type mentioned—the soluble concentrates, flowables, and wettable powders—requires suspension in water for effective application, making the correct answer encompass all of the options given.