Reporting a Problem on a Microsoft Exam
This quickie Ask a Certification Expert podcast from Microsoft Learning explains the procedure for reporting errors in exam questions and how they handle such complaints (um...feedback).
Additional Notes: This process really exists to help identify and correct problematic questions, not boost your exam score. It's not mentioned in the video, but if you visit the Microsoft exam policies page it references, you'll learn:
1) You must submit your request for evaluation of a test item within 3 days of taking the exam.
2) Even if Microsoft agrees with you, "In most cases, exams are not rescored," though Microsoft may offer you a free retake. So think of reporting a problem question as a public service to future exam takers, which may well include yourself.