Queries - Index choosen by the optimizer

Query IndexType select top 10000 *  from   SalesOrder  Clustered Index Scan select  *  from   SalesOrder where SalesOrderDetailID>10000 and SalesOrderDetailID<20000  clustered index seek select  *  from   SalesOrder where ProductID=714 and ProductID=715  constant scan select  *  from   SalesOrder where ProductID=714 or ProductID=715  Clustered Index Scan select  SalesOrderID,OrderQty,UnitPrice  from   SalesOrder where ProductID in(714,715)  Clustered Index Scan select  OrderQty,UnitPrice  from   SalesOrder where SalesOrderID =43659  Index Seek select  OrderQty,UnitPrice  from   SalesOrder where SalesOrderID >40000  Index Seek select  *  from   SalesOrder where SalesOrderID >40000  Clustered Index Scan select  *  from   SalesOrder where ProductID=714 or ProductID=715 order by SalesOrderID  Clustered Index Scan select  OrderQty,UnitPrice  from   SalesOrder where SalesOrderID =43659 order by SalesOrderDetailID  Index Seek select  OrderQty,UnitPrice  from   SalesOrder order by SalesOrderDetailID   Clustered Index - SalesOrderDetailID Non Clustered   - SalesOrderID,OrderQty,UnitPrice Clustered Index Scan