Which of the following activities requires a license?

The activity that requires a license from the options provided is the use of restricted-use pesticides commercially. Restricted-use pesticides are those that can pose a risk to human health or the environment, and as such, their application is heavily regulated. To ensure safe and appropriate handling, individuals who plan to apply these pesticides in a commercial setting must obtain a license, which typically involves completing training and passing an examination. This licensing ensures that applicators understand the potential risks, proper application methods, and regulations surrounding the use of these substances.

In contrast, selling general use pesticides does not always require a specialized license beyond standard retail requirements, as these products are considered safe for public use with clear directions. Private gardening does not necessitate a license since it involves the application of pesticides on one’s own property for personal use. Applying pesticides as a volunteer typically does not require a license, especially when the products used are not classified as restricted-use, making it suitable for non-professionals to engage in without formal training or licensing.