Represent the following relations among classes using UML diagram. 1. Students credit 5 courses each semester. Each course is taught by one or more teachers. 2. Bill contains number of items. Each item describes some commodity, the price of unit, and total on this price. 3. An order consists of one or more order items. Each order item contains the name of the item, its quantity and the date by which it is required. Each order item is described by an item type specification object having details such as its vendor addresses, its unit price, and the manufacturer.