Final answer:
The allocation approach is used in a DDBMS to determine the optimal distribution of data by combining fragmentation and replication.
Step-by-step explanation:
The approach to setting up a distributed database management system (DDBMS) that combines fragmentation and replication is known as the allocation approach. In distributed databases, data is not stored in one location but is dispersed across various network sites, which can improve performance and availability. The allocation approach involves deciding where to locate fragments of the database, ensuring that data is distributed in an optimal manner.