Create an ER diagram based on the following requirements. Show entities, relationships, and attributes. Groundhog Bus - a bus charter company keeps track of:

• For each employed driver: fullname (composed of fname and lname), birthdate, age, unique SSN, unique dln (drivers license number).
• For each bus owned: unique blpn (bus license plate number), make, model, year, no_of_seats.
• For each charter assignment: unique caid (charter assignment id), datebegin, timebegin, dateend, timeend, startlocation, endlocation.

Additional requirements:

• Each driver can be assigned to a number of charter assignments but does not have to be assigned to any.
• Each bus can be assigned to a number of charter assignments but does not have to be assigned to any.
• Each charter assignment must have one driver and one bus assigned to it.
• Each driver is certified to drive one or more buses.
• Each bus must have at least one driver certified for it.