$($a$)$ With example describe all types of relationships in class diagram $[10$ Marks$]$

$($b$)$ A bank system contains data on customers $($identified by name and address$)$ and their accounts.

Each account has a balance and there are $2$ type of accounts: one for savings which offers an interest

rate, the other for investments, used to buy stocks. Stocks are bought at a certain quantity for a

certain price $($ticker$)$ and the bank applies commission on stock orders. Draw a class diagram to

illustrate the system