The control procedures of the Kary Company include the following:

1. Credit department authorization for all credit sales.

2. Billing department matching of sales order and shipping documents before preparing invoices.
3. Internal verification by accounts payable clerks of the mathematical accuracy of vouchers.
4. Overtime work must be approved by the employee's supervisor.
5. An accounting clerk compares the coding of sales invoices with the chart of accounts.
6. Two signatures are required on every check.
7. A cashier department supervisor makes daily cash counts of register readings and cash on hand.
8. The head cashier makes daily cash deposits intact.
Assume in each case that evidence of performance is available in the form of initials, signatures, and stamps.
Required:

a. Indicate the internal control principle that pertains to each procedure.

b. Identify a compliance test that may be performed to determine whether the prescribed control procedures are functioning properly.

c. Identify a substantive test of transactions that may be performed for each procedure.