In a fictional database about customers purchasing tour packages to various places at different prices, data operations of different kinds are performed. Try to categorize the following operations into data retrieval, online analytic processing, or data mining:

a. Find names of customers who have purchased tours that cost less than 300.

b. List the names of the customers, the number of tour packages that the customers have purchased, and the total cost for the tours.

c. Calculate the differences in quarterly sales of tours between this year and the previous two years.

d. Find a rule such as 'If customers purchase a tour package to France, then it is 85% likely that the same customers also purchase a tour package to Spain '.

e. From the customer purchase history, build a model for predicting the kinds of customer who are likely to purchase tours to a certain country.