(Original post by Juno)
You're forgetting - or maybe just not realising - that there are people who actually know nothing. Some students genuinely won't be able to tell the answer. These questions are designed to weed out the students who can do nothing from the ones who can do something, but not much. If all the questions were hard then all the students with less ability would score zero. It's the same idea as distinguishing A* from A.
Even with the better students some might not really know the basics, and others might not pay attention. So whilst it's an easy mark for you, some of the more able students may lack focus to answer the stuff they see as stupid.
I have no idea what your point is. However, the question is relying on students hearing a phrase and picking out which is the correct word in that phrase. Then they have to understand that "17" is the way that phrase is represented. So it's testing a few things, which you as a more able student will not realise.
Also, just because the word sounds similar doesn't mean students will recognise it or realise it's the same word. Maybe the student has made a mistake like this before and is wary