Draw a context data flow diagram and a level 0 data ow diagram from the scenario below:

Boston Fish Company is a fishing company based near the ocean in northwest Massachusetts. Its specialty products are salmon, cod, and halibut. Boston Fish Company sells only to commercial customers, who are typically grocery store managers. Each day, customers come to the Bellingham Fish Company's location to pick up fresh fish products. All billing is handled via mail.

Business Processes: The processing steps that the Boston Fish Company follows to keep track of its sales and prepare billing statements are described below: Process 1: Each customer comes to the counter to request a fish order. The order is submitted to the sales clerk using a paper form that the customer fills out. The seafood order is then assembled for the customer (e.g., the order is packaged). For purposes of this exercise, we can assume that orders can always be filled. Also, we can assume that the sales clerk assembles the order. The sales clerk then creates a simple hand written sales slip that is prepared using a paper pad that can create "carbon copies" of a sales slip (i.e., the original sales slip, plus a carbon copy). The carbon copy of the sales slip is given to the customer along with the seafood. This sales slip is for the customer's records. The original copy of the sales slip is not given to the customer, but is instead stored by the sales clerk in a large cardboard box on a shelf next to the cashier's counter. The box holds all of the sales slips for the day. Process 2: At the end of the day, after the store has closed, the sales clerk removes all of the sales slips from the box and calculates information relating to the sales for the day. Specifically, a simple summary report of the total sales (e.g., sales by types of seafood, sales by customer) is prepared by the sales clerk and is given to the general manager of the Bellingham Fish Company. Once the daily sales report is completed, the sales clerk puts all of the sales slips into a manila envelope and hand delivers the envelope to the accountant. Process 3: Upon receiving the manila envelope of information, the accountant immediately examines the information on each sales slip to check for calculation mistakes. If a calculation mistake exists, then the error is corrected. She makes a notation on each sales slip to indicate that the sales slip has been examined and then stores the verified sales slip information in a large black file cabinet located in the back corner of her office. Process 4: At the end of the week, the accountant retrieves all of the sales slips collected over the week to prepare a weekly billing statement for each customer. Upon completion, each of these billing statements is sent via e-mail from the accountant to each customer who has made a purchase during the previous week.