I took the '30 tough questions' from PM Zilla. I noticed three questions were from Oliver F Lehmanns 175 question sample test. I have no problem seeing the smae question in different places as I have seen it before. I had the correct answer on the Lehmann test, so I selected the same answer on the PM Zilla 30 Tough Question test and they were marked as incorrect. First off, why is it correct on the Lehmann test, but not the PM Zilla quiz (or vice versa) and second, which one do I believe?

Question 1