It s defenietly unit 3 since I have done it last year and passed... My advice is to revise as much as possible and you'll be fine with it. Wish you all the best!
If you have learnt about simultaneous equations then its deffo unit 3.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.