You work as an application developer at Contoso.com. You use Microsoft .NET Framework 3.5 and Microsoft ADO.NET to develop an application that will connect to the Microsoft SQL Server 2005 database. Your application contains the following code.   string queryString = "Select * from dbo.Users"；  SqlCommand command = new SqlCommand（queryString， （SqlConnection）connection））；   You want to get the value that is contained in the first column of the first row of the result set returned by the query.   What should you do？ （）