Their all so good its hard to chooseYour teacher will be the one marking it so their suggestion is a good one.
Italian Unification is also interesting.
Mussolini is also fine.
I wouldn't try to link Italian Unification with Mussolini due to the sheer size of that topic and the word limit as you would have to cover a period of over 80 years (unification in 1861 and Mussolini coming to power 61 years later for 23 years).
Which one should I choose?