(a) Clustering
The diagram shows two groups of data points enclosed in separate ovals, representing data grouped by similarity without predefined labels — which is clustering, a form of unsupervised learning.
Clustering is a subcategory of unsupervised learning where the model groups similar data points together based on patterns, without any predefined class labels. The diagram clearly shows two distinct clusters (ovals), making option (a) the correct answer. Regression predicts continuous values (supervised), classification uses labeled categories (supervised), and reinforcement learning uses rewards/penalties — none of which match the diagram.