4. Design an ER diagram for the following situation: Land masses are either islands or continents. All land masses have a name and an area; the name is the key. Some continents are connected to each other, e.g., Asia is connected to Europe. No island is connected to any other island or to a continent. Bodies of water are either oceans or straits. A body of water has a name (the key) and an area. Islands may be either located in one ocean (e.g., Hawaii is in the Pacific Ocean) or separated from a continent by a strait (e.g Honshu is separated from Asia by the "Sea of Japan'") . You should not assume that a strait is adjacent to only one continent or to only one island. (20 points)