The subject of data mining deals with

A) methods for developing useful decision-making information from large data bases.
B) keeping data secure so that unauthorized individuals cannot access the data.
C) computational procedure for data analysis.
D) computing the average for data.

Data mining is the process of using computational techniques to discover patterns and information from large sets of data. The goal of data mining is to extract useful and relevant information and insights from large amounts of data. It involves using statistical and machine learning algorithms to analyze data and identify patterns that can be used to make better decisions. Therefore, option A is the correct answer. Option B is incorrect because it describes data security, not data mining. Option C is too broad and may describe other computational processes beyond data mining. Option D describes a basic statistical concept and does not capture the essence of data mining.