The Field Extractor Utility (FX) is a tool that helps you extract fields from your events using a graphical interface or by manually editing the regular expression2. The FX has a button that displays events that do not contain extracted fields, which is the Non-Matches button2. The Non-Matches button shows you the events that do not match the regular expression that you have defined for your field extraction2. This way, you can check if your field extraction is accurate and complete2. Therefore, option B is correct, while options A, C and D are incorrect because they are not buttons that display events that do not contain extracted fields.