HI!
Which is hardest? I think it depends on what you are most into - for me Met was the easiest as it is what intrests me...... and the technical one was hardest as I was really not that into the "why it flys" bit.....
Dont get too fased by it all - can you take a break and do one of one the other ones first? At the end of the day they are not that difficult - but that is easy to say once you have sat in the romo and done them!
Relax, take your time - and have another go.
Is there any scope to ask for feedback so you know which questions you got wrong?
All the best,
FW