Electro Inc. sells electrical components to large department stores and also has a few cash sales to electricians. Sales invoices are prepared for all sales. Cash sales are recorded to the cash receipts journal and cash is deposited to the bank each day. All sales to large stores are credit sales and are handled by sales clerks by telephone or fax. The sales clerk takes the customers request, checks the authorized customer list for credit limits (if it is a credit sale), prepares the sales invoice, and sends one copy to the inventory control department, who sends the ordered goods to the shipping department. For cash sales, the inventory control clerk brings the items sold to the sales counter and the goods are given to the purchaser at the time of sale. For credit sales, the shipping clerk signs the inventory control copy of the sales invoice and then prepares a shipping invoice. A third copy of the sales invoice is forwarded to the accounting department so that a clerk can enter the sale into the sales journal. The shipping invoices are maintained in the shipping department in case a shipment needs to be checked. All goods are shipped FOB shipping point. Required: a. Design three substantive audit procedures (other than analytical procedures) that will provide evidence of the validity of sales. Identify the procedure (trace, compare, vouch, and so on), the documents you are using, and explain why these procedures will show whether recorded sales are valid. b. Design three substantive audit procedures (other than analytical procedures) that will provide evidence of the completeness of sales. Identify the procedure (trace, compare, vouch, and so on), the documents you are using, and explain why these procedures will show whether recorded sales are complete.