Final answer:
In an acquisition, 'Purchase' and 'Inventory type' are classes paired in a duality association, as they represent two interconnected aspects of the same process.
Step-by-step explanation:
In an acquisition process, the classes that would be paired in a duality association are Purchase and Inventory type. A duality association is established between two classes when they represent two aspects of the same process. In this case, the purchase class involves the process of acquiring goods or services, while the inventory type class pertains to the categorization and storage of those acquired goods within the company's inventory system. These two classes are inherently linked as the types and quantities of purchases directly affect the inventory levels. On the other hand, service acquisition and cash disbursement, cash disbursement and cash, and purchase and purchase return are classes that would not typically be paired in a duality association as they represent distinct business processes or transactions rather than two aspects of the same process.