Final answer:
The first generation of major data models created during the 1960s and 1970s were a. the hierarchical and network models. They utilized tree-like and graph-like structures to organize and retrieve data before the emergence of the relational model.
Step-by-step explanation:
The first generation of major data models that were created during the 1960s and 1970s is hierarchical and network models. These two models laid the foundation for organizing and retrieving data in computing systems. The hierarchical model organizes data in a tree-like structure where each child record has only one parent, while the network model allows each record to have multiple parent and child records, which creates a graph-like structure. Both were widely used before the advent of the relational model in the late 1970s, which simplified how users could interact with data using a table-based structure. The file system model is a more basic way to organize data in files and directories, but it was not considered a major data model. The object-oriented model, while influenced by earlier models, wasn't fully developed until later in computing history.