Draw E /R diagrams for the following situations involving weak entity sets. In each case indicate keys for entity sets.

a. Entity sets Courses and Departments. A course is given by a unique department, but its only attribute is its number. Different departments can offer courses with the same number. Each department has a unique name.
b. Entity sets League, Teams, and Players. League names are unique. No league has two teams with the same name. No team has two players with the same number. However, there can be players with the same number on different teams, and there can be teams with the same name in different leagues.