ADO.NET :: Error - Can't Implicitly Convert Type 'System.Linq.Iqueryable

If I have below code, how to make it work as it has below compile error:

Error: cannot implicitly convert type 'System.Linq.Iqueryable<system.data.DataSet> to 'System.Data.Dateset'. An explicit conversion exists.

public DataSet GetProductList()
{
using (var sdatabase = new DatabaseDataContext())
{
IQueryable<DataSet> result = wmsdatabase.ExecuteQuery<DataSet>(@"SELECT productid, productname from product group by productid, productname").AsQueryable();
return result; // Compile error here
}
}