An example of a pesticide formulation that must be used dry is?

The correct choice is granule, which is a formulation that is specifically designed to be used in a dry, solid state. Granules are small particles that can be spread on the ground or applied directly to specific areas, effectively targeting pests in their environment without the need for a liquid carrier. This method can help in managing pests in soil and on plants where moisture is not desirable.

In contrast, the other formulations listed are all intended to be used in a wet or liquid state. Liquid formulations require water as a carrier for application, aerosol formulations dispense chemicals in a mist or spray, and emulsifiable concentrates are combined with water to create a stable mixture for application. This essential distinction helps to understand the specific application requirements for different types of pesticide formulations.