Final answer:
A boat-building company needing to use a lake for testing boats would require a Proprietary lease, not a Grounds Lease, for using the property for their business needs.
Step-by-step explanation:
If a boat-building company wants to use a lake belonging to a landowner to test their boats, they would typically need a Proprietary lease. A Proprietary lease is associated with the use of the property for business purposes, giving the company the right to occupy and use the space for their business activities, which in this case is testing boats. Conversely, a Grounds Lease tends to involve leasing undeveloped land for the lessee to improve, which is not pertinent to the boat builder's aim to simply use the lake.