In SQL, specify the following queries on the database specified in Figure 3.5 using the concept of nested queries and the concepts described in this chapter.
a. Retrieve the names of all employees who work in the department that has the employee with the highest salary among all employees.
b. Retrieve the names of all employees whose supervisor's supervisor has '888665555' for Ssn.
c. Retrieve the names of employees who make at least $10,000 more than the employee who is paid the least in the company.