Concept:A heterogeneous distributed database is one in which different database management systems are used at different locations, while data is still shared across all nodes.
Explanation:In a distributed database, data is stored at more than one location or node.
If all locations use the same DBMS software, the system is homogeneous.
If the locations run different DBMS software, possibly from different vendors or with different data models, the system is heterogeneous.
Among the options, only C and D mention different DBMS at each location.
However, for the database to be truly distributed, its data must be spread across all nodes and not kept at one central site.
Option C says data is not distributed, so it cannot define a distributed database.
Therefore, the correct definition includes different DBMS at each location with data distributed across all nodes.
Answer:D. Different DBSM is used at each location and data are distributed across all nodes.