A small business builds certain products to sell to customers through sales channels. There are many sales channels and each channel can sell many products and each product can be sold by many channels. Each channel has many salespersons. One salesperson can only belong to one channel. Within the channel, a salesperson may manage many other salespeople. A salesperson is managed by only one salespeople. A salesperson can be an agent for many customers. A customer is managed by one salespeople. A customer can place many orders. An order can be placed by one customer. An order lists many inventory items (products). An inventory item may be listed on many orders. An inventory item (product) is assembled from many parts. A part may be assembled into many inventory items. The company hires two kinds of employees, channel managers and production workers. One channel manager can manage many channels and a channel can only be managed by one channel manager. The salaries for the channel manager and the production worker are different. The channel manager is paid by base salary plus commission while the production worker is paid by hourly. Many employees assemble an inventory item from many parts. A supplier supplies many parts. A part may be supplied by many suppliers. Please draw an ER diagram to design a database for this company with the fewest entities and necessary relationships among these entities. You must add key attributes for all entities. You may only add essential non-key attributes that are sufficient to complete the ER diagram.