Garrison Boutique, a small novelty store, just spent $4,000 on a new software program that will help in organizing its inventory. Due to the steep learning curve required to use the new software, Garrison must decide between hiring two part-time college students or one full-time employee. Each college student would work 20 hours per week, and would earn $15 per hour. The full-time employee would work 40 hours per week and would earn $15 per hour plus the equivalent of $2 per hour in benefits. Employees are given two polo shirts to wear as their uniform. The polo-shirts cost Garrison $10 each. What are the sunk costs for Garrison?