Which liquid pesticide formulation has a small amount of active ingredient, often 1% or less?

The correct choice is the ready-to-use (low-concentrate) solution. This formulation is designed for convenience, containing a small amount of active ingredient, typically around 1% or even less. Such low-concentration solutions are often pre-mixed and are intended for direct application without the need for further dilution, making them user-friendly and suitable for homeowners or small-scale applications where precise measurement and mixing are not required.

In contrast, concentrated solutions generally contain a higher percentage of active ingredients and require dilution before use. Emulsifiable concentrates include a higher concentration of active ingredients that can be mixed with water for application; they are not suited for direct use without proper dilution. Suspension concentrates often contain solid active ingredients that need agitation to prevent settling before application, which usually involves a higher concentration of the active component.

Thus, the ready-to-use (low-concentrate) solution is the formulation specifically characterized by its low concentration of active ingredients, making it the most appropriate answer in this context.