Clustered data emerge when the data from the entire sample can be grouped into a variety of different categories, refers to as clusters. Each cluster involves numerous observations, giving the data a “clustered” or “hierarchical” structure, with each observations encapsulated within the cluster.
Also, if we plot a series of numbers on a graph and we will see several of our dots gathered together, we have a cluster
From the above definition of clustered data the only option that is fitting into it is option C .
