For each of the following internal controls:
(a) identify the most relevant general audit objective(s) for the control activity, (b) design an appropriate test of control for the control activity, (c) choose one of the general audit objectives identified in (a) and design an appropriate substantive test for it.

Please note: Do not use analytical procedures unless an accounting estimate is involved.

(1) The audit client's internal purchase requisition forms are serially numbered/prenumbered.
(2) Sales staff use a barcode scanner to obtain the product name and selling price to avoid potential price errors in a manual process.
(3) Security cameras are installed in all warehouses, where inventories are stored, to prevent and identify theft.