Answer: Know the prices of all goods they might buy.
Explanation: Assets not acquired become property precisely because their use by one person means that others cannot use them. When a good has no owner (for example, in a state of nature), the question of acquiring it and making it the property of one is a matter, as with all actions, of choosing a course of action over another. However, given a system of property rights that determines how goods can be acquired fairly, interactions with others do not necessarily arise.