Beverly Spends $100 on a Teeth Whitening Kit

Beverly spends $100 on a teeth whitening kit.After one application,her gums are inflamed and it feels like her mouth is on fire.Beverly is trying to decide whether to apply the treatment again,or throw the kit away.The opportunity cost of a second application is:

A) $100.
B) the pain and suffering involved with the second application.
C) $100 + the pain and suffering involved with the second application.
D) $100 + the pain and suffering involved with the first and second application.