A few years ago I spent many a night burning midnight oil doing my national ATPLs. Being totally at odds with many questions, I just learned that A, B, C or D was the answer to questions I couldn't get my head around and believe me there were many such questions. Even the next day when we looked for clarification from our ground instructors we were just told to learn the answer because that is what the examiner is looking for.
It is really refreshing to see that JAA have retainded some of the history of the old national systems!!!
Well done for seeking out the correct answer but remember in the ol' exam just go with, in this case 'B'.