Consider an ONLINE$\_$FREELANCE$\_$MARKETPLACE database system in which members $($clients and freelancers$)$ participate in the posting and undertaking of projects. The data requirements for this system are summarized as follows:

$-$ The online platform has members, each of whom is identified by a unique member number and is described by an email address, name, password, home address, and phone number.

$-$ A member may be a client or a freelancer. A client has a billing address recorded in the database. A freelancer has a bank account number and routing number recorded in the database.

$-$ Projects are posted by clients for freelancers to bid on and are identified by a unique project number assigned by the system. Projects are also described by a project title, a description, starting bid price, bidding increment, the start date of bidding, and the end date of bidding.

$-$ Freelancers submit bids for projects they are interested in$.$ Bid price and time of bid are recorded. The freelancer with the most suitable bid at the end of the bidding period is awarded the project, and a contract between the client and freelancer may then proceed.

$-$ The client and freelancer may record feedback regarding their completed projects. Feedback contains a rating of the other party participating in the project $(1-10)$ and a comment.

a$)$ Design an enhanced entity$-$relationship diagram for the ONLINE$\_$AUCTION database.

b$)$ Map the resulted schema into a relational schema and specify all primary keys and foreign keys.