What type of application uses nozzles located at the end of long hoses trailing from the boom?

The correct answer accurately describes a method known as deep-water injection, which involves the use of specialized nozzles positioned at the end of long hoses that extend from a boom. This technique enables precise targeting of aquatic weeds or pests by allowing for the application of pesticides or herbicides directly into the water column, deep beneath the surface. This method is particularly effective for controlling aquatic vegetation in deeper areas where other application techniques may not reach.

In contrast, aerial applications are typically carried out from aircraft, spraying chemicals directly from the air, and do not involve hoses or booms in this manner. Handgun spraying refers to a method where a handheld spray nozzle is used, allowing for manual targeting, but it does not utilize long hoses or a trailing boom format. Subsurface injection is a technique that typically involves inserting a device directly into the substrate of the water body to deliver a product, rather than trailing hoses that deliver from above. This contextual understanding helps clarify why deep-water injection is the correct and appropriate choice for the described application method.