You design a SQL Server 2008 Reporting Services （SSRS） solution. You create a report by using Microsoft Visual Studio .NET 2008. The report contains the following components： A dataset named Customer that lists all active customers and their details. The dataset accepts no parameters. A dataset named SalesHistory that lists all sales transactions for a specified time period and accepts year and month as parameters. You need to ensure that a summary of sales transactions is displayed for each customer after the customer details. Which component should you add to the report？ （）