This is a PMBOK definition, failure costs are the cost of poor quality; costs spent during and after the project because of failures to meet the requirement.
as for other choices:
>Internal costs : this is a category of failure costs, failures found by the project team.
>Prevention costs : this is part of cost of conformance. investments in preventing non-conformance.
>Cost of defects : this is part of internal costs.
please refer to section 22.214.171.124 Cost of Quality (COQ) in the PMBOK Guide it includes more clarifications.
Moderators: Yolanda Mabutas, Ahmed Amin, Scott Gillard, Mary Kathrine Padua, ERIC BARTLETT, Gail Freedman, Kevin Nason, Steven Mudrinich, PMP, Mark Wuenscher, PMP, John Wolverton, Tracy Shagnea, PMP, Jada Garrett
This interview with Simona Fallavollita (LinkedIn Profile) was recorded at the magnificient Project Management Institute (PMI)® Global Conference 2017 in Chicago, Illinois. We discuss the how, what, why and when of the changes that are coming to the PMP exam.