Which of the following statements regarding relevant costs and sunk costs is incorrect? Select one: a. A serious drawback associated with the incremental approach of relevant cost study is that the incremental approach is cumbersome if more than two alternatives are considered. b. The type of cost presented to management for an equipment replacement decision should be limited to relevant costs. c. A sunk cost is a cost which cannot be avoided because it already has been incurred. d. Relevant costs can be studied using an incremental approach but should not be considered with a full project approach.