Structure A. Its preferable to evaluate each point directly after, in a new paragraph to make it clear to the examiner, rather than a bunch of evaluation paragraphs right at the end of your essay. But really everyone is different, it wouldn't matter if you used either structure as long as you have the correct amount of points and marks allocated to each K(4) A(4) A(6) Ev(6).
I have my exam tomorrow and have really been practicing my evaluations, they are key.
Oh and btw don't worry if you run out of space on the actual paper, most of us will, just ask for more paper and you'll be able to continue on there.
Hope I was able to help and goodluck!