Among the customers in South superstore, which customers ordered more than 3 times in 2015? State the name of the customers.
name of the customers refers to Customer_Name; in 2015 refers to "Order Date" BETWEEN '2015-01-01' AND '2015-12-31'; more than 3 times refers to count(Order_ID) > 3
SELECT DISTINCT T2.`Customer Name` FROM south_superstore AS T1 INNER JOIN people AS T2 ON T1.`Customer ID` = T2.`Customer ID` WHERE STRFTIME('%Y', T1.`Order Date`) = '2015' GROUP BY T2.`Customer Name` HAVING COUNT(T2.`Customer Name`) > 3