Which broad area of data mining applications analyzes data, forming rules to distinguish between defined classes?

Classification.

Explanation:

Classification is the wide field of data mining apps that analyzes data and establishes rules for making a distinction in specified classes.

Data mining is a method that corporations use to transform the raw information into valuable information. Corporations can understand something about their clients through using technology to identify trends in large quantities of info to create more successful marketing campaigns, increase revenue and reduce costs.