What is defined as a business that propagates plants under the "plant industry law"?

The correct answer is the term commonly used to define a business that propagates plants under the "plant industry law." A nursery is specifically designated for the cultivation and sale of plants, including trees, shrubs, and flowers. This definition aligns with regulatory contexts where nurseries are often required to adhere to specific guidelines regarding plant health, pest management, and propagation practices to ensure compliance with local agricultural and environmental laws.

The other terms do not encapsulate the full scope of propagating plants as a nursery does. A retail dealer typically refers to a business that sells finished goods directly to consumers but may not engage in the propagation process, while a stock dealer generally focuses on the trade of market securities rather than plant propagation. A seed supplier provides seeds and may not deal with the cultivation or sale of live plants in the same manner that nurseries do. Thus, nurseries hold a distinct position under the plant industry law as entities responsible for growing and selling living plants.