A company database needs to store information about its employees (identified by ssn, with salary, phone and title as attributes) and departments (identified by dno, with dname and budget as attributes), given the additional information below. Employees work in at least one department; each department is managed by exactly one employee and we want to know the date the manager started managing the department. An employee may be assigned at most one mentor, who is another employee, to get advice from on job and career development related issues. An employee may mentor several other employees (the mentees) but not all employees are required to serve as mentors. We want to store information about a mentor-mentee relationship and when it was established; we are not interested about such a relationship once either the mentor or the mentee leaves the company. Draw an ER diagram to capture the situation described above. Make sure you capture as many integrity constraints as possible and explicitly mention those that cannot be captured by the ER diagram (if any). Note: Make sure that your E/R diagrams are clear and unambiguous (e.g., your bold lines look unmistakably bold, your arrowheads look unmistakably like arrowheads, etc.). You will not receive the benefit of the doubt in the presence of ambiguity.