How to pass values from data access layer(dal) to business layer(bal) in 3 tier architecture ?

http://pawantechit.blogspot.my/2011/09/3-tier-architecture.html

public class DataLayer
{
    
    public DataSet Get_Data(string SqlStmt)
    {
        SqlConnection con = new SqlConnection(your connection string);
        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter(SqlStmt, con);
        da.Fill(ds);
        return ds;
    }
}

public class BLayer
{
    
    public DataSet Get_Data()
    {
        DataLayer dl = new DataLayer();
        return dl.Get_Data("select EmpNo,Ename,Job,Mgr,Sal,Comm from Emp");
    }
}