Given the following relational database schema:

Employee=(ID, name, position, officeN, phoneN,age)// assume the name is unique.

Committee =( title, meetingDate, startTime, endTime, location)// You may use <,>,=,!= between dates and times.

Membership= ( ID, title, task) // task = member or chair.

Use a minimum number of operations and tables to express the following queries by SQL statements:

a. List the name of every employee who is a member (not chair) of at least three committees.

b. List the name of every employee who serving on every committee.

c. For every employee, list the ID, name and number of committees he/she is serving on as member or chair.

d. List the name of every employee who only serves ( as member) on committees that meets in location H345.