Problem: Bob and Carrie, two senior audit managers working for Jones CPA Firm are currently completing the audit of NexGen Enterprises, Inc., a distributor of textbooks and educational materials across the United States, Canada, and Mexico, and an ongoing audit client. In prior audits, Jones CPA firm have noted that the client's system of internal control has been effective and strong. In addition, it has been further noted that the client operates and maintains a strong and independent internal audit function staffed by competent and experienced professionals. Based on this information, which of the following audit strategies are likely to be the most appropriate?