You are given a description of a hypothetical, tiny database system. The description is incomplete and each student should fill in the details in any way she$/$he thinks. Your task: Construct an ER diagram for a database system that models data of the following situation.

$$ You are creating a database for a stock trading company.

$$ The company has clients and financial officers.

$$ Each client is either an individual or another legal entity $($e$.$g$.$ another company$).$

A client has a name, social security number, address, contact information, the date that entered the database system, and also a ranking that the trading company keeps internally $($you can decide what the ranking is supposed to be about$).$

$$ Financial officers have a name, employee ID$,$ social security number, and other HR information $($e$.$g$.$ annual salary, bonus, etc $$ you should decide about this$).$

$$ There are contracts that one client $($or more clients together in one contract$)$ have with the hedge fund. You should decide about the details of each contract.

$$ One constraint is that each contract has exactly one financial officer who is responsible and at least one client.

Your task is to:

Fill in missing information, i$.$e$.$ complete the story in any way you like,

add at least one more constraint to the description, and

draw an ER diagram for the above description and anything else you decided for $(1)$ and $(2).$

IMPORTANT: You can only use the ER diagram conventions we introduced in class. No other source can be used.