Final answer:
It can be either true or false that only one brokerage is authorized to act on behalf of the client, depending on the specific agreement. For proprietary colonies, it is false that proprietors only had the responsibility to collect profits, as they had numerous other duties.
Step-by-step explanation:
The statement that only one brokerage is authorized to act on behalf of the client can be true or false depending on the agreement between the client and the brokerage firm. Such an arrangement where only one brokerage is authorized is known as an exclusive brokerage agreement. However, clients may choose to work with multiple brokerages under non-exclusive agreements. Therefore, without context specifying the nature of the contractual agreement, one cannot definitively say that only one brokerage is authorized to act on behalf of the client as a general rule.
Regarding the question about a proprietary colony, it is false to say that Proprietors in a proprietary colony have no responsibilities except to collect the profits. Proprietors typically had numerous responsibilities, including maintaining the colony, managing relations with the indigenous population, trade, defense, and setting up a form of governance.