Question 5: Let the data set of transactions consist of the sets {1 ,2,3,4,5}, {1,2,5}, {1,2,3}, {1,2,4}, {2,3,4}, {2,4,5}, {1,3}, and {3,4}. Suppose that the support threshold for a frequent itemset is 4 (Le, an itemset hastg appear at least 4 times in the transactions to be frequent), how many frequent itemsets can be found based on this data set? (Hint: please use APRIORI algorithm and start with all the 1item itemsets)