Suppose that you have started a new job as a data analyst in the XYZ Retailer Company. The company has a vast amount of sales/transaction data and customer data. You have been assigned to identify different groups of customers based on their purchasing behaviour to improve the overall sales. However, the XYZ Retailer Company does not have any previous criteria for grouping these customers. Now, answer the following questions in your own words: A. Explain what type of learning (i.e., supervised, unsupervised) will accomplish this task. (3 marks) B. Discuss briefly what data mining method you will choose and justify your answer. (4 marks) C. How do you determine the optimal number of groups of customers? (3 marks)