Which of the following would be classified as an internal failure cost on a quality cost report?

A) Quality improvement projects.
B) Supervision of testing and inspection activities.
C) Debugging software errors.
D) Warranty repairs and replacements.

Debugging software errors would be classified as an internal failure cost, as it is a cost incurred to address a defect or error discovered during the production or testing process. A is incorrect as quality improvement projects are typically considered prevention costs. B may be a prevention cost if it involves activities to prevent defects from occurring in the first place, but it is not clear from the given information. D is classified as an external failure cost, as it involves the cost of repairing or replacing a defective product that has already been shipped to customers.