Final answer:
The manager of a department store conducting interviews with all employees in randomly selected departments is utilizing a Cluster survey design.
Step-by-step explanation:
The survey design described in the question is known as a Cluster survey design. This methodology involves selecting groups, or 'clusters', at random and then collecting data from all members within those selected clusters. In the context provided, the manager is choosing entire departments as clusters and interviewing every employee within those departments. This differs from a Stratified survey where individuals are chosen based on specific subgroups, or a Simple Random survey where every individual has an equal chance of selection regardless of their group. A Systematic survey would involve selecting individuals based on a fixed sampling interval, which is not the case here.