For the following data requirements analysis description, develop an Entity-Relationship Diagram as a conceptual model that captures all of the requirements to the fullest extent possible.

A medical supply store decides to expand its offerings online. Everyone knows that you are taking Applied Databases, so you are asked to design a database for the store. After brainstorming with the store managers, you come up with the following specification:

The store has multiple departments, identified by their names;
Each department may have many employees but (at most) one of them is the department manager;
Employees are identified by their names. We also need to record their salaries. Each employee works in exactly one department. Managers are employees as well, each with a salary higher than all other employees in the department he/she manages;
The store sells various items identified by item ID's. Exactly one department carries each item, while each department may carry many items. For each item, we also need to keep a short description and its quantity in stock;
The store deals with a number of suppliers identified by their names. We need to record their addresses. Each supplier supplies an item at a particular price. A supplier may supply any number of items, and each item must be supplied by at least three suppliers (probably at different prices);
The store receives orders identified by order ID's. Each order has a date, a shipping address, and may include different quantities of multiple items.
Given the above description, complete the following. You must use the Information Engineering format discussed in the course video and slides for the ER diagram notation. You may use either the data modeling tool in MySQL workbench, or a freeform drawing tool of your choice, but the notation must meet the specification for course ER diagrams.

Draw an ER-diagram for the database, identifying:
(a) all the entity sets;
(b) all the relationship sets and their multiplicity;
(c) the primary key for each entity set (and weak entity set, if any) and each relationship set.
(d) (optional) additional (non-specified) attribute(s) for the entity sets that are appropriate.
Indicate (what and why) any feature(s) or property(ies) in the above description that are NOT captured by your ER-diagram