Answer following with Relational Algebra.

a. List the names of all employees who work in the department that has the employee with the highest salary among all employees.

b. List the names of all employees whose supervisors supervisor has 888665555 for Ssn.

c. List the names of employees who make at least $10,000 more than the employee who is paid the least in the company.

EMPLOYEE \begin{tabular}{|l|l|l|l|l|l|l|l|l|l|} \hline Fname & Minit & Lname & Ssn & Bdate & Address & Sex & Salary & Super_ssn & Dno \\ \hline \end{tabular} DEPARTMENT \begin{tabular}{|l|l|l|l|} \hline Dname & Dnumber & Mgr_ssn & Mgr_start_date \\ \hline \end{tabular} DEPT_LOCATIONS \begin{tabular}{|l|l|} \hline Dnumber & Dlocation \\ \hline \end{tabular} PROJECT \begin{tabular}{|l|l|l|l|} \hline Pname & Pnumber & Plocation & Dnum \\ \hline \end{tabular} WORKS_ON \begin{tabular}{|l|l|l|} \hline Essn & Pno & Hours \\ \hline \end{tabular} DEPENDENT \begin{tabular}{|l|l|l|l|l|} \hline Essn & Dependent_name & Sex & Bdate & Relationship \\ \hline \end{tabular}