no pedal.
however if the piano in the exam is a grand, and has a middle "selective" pedal, you could use this to sustain the minims that appear in the bass, without blurring the arpeggios over the top. my knowledge on baroque styles is hardly comprehensive, so there'll be plenty of others on here who'll give more useful advice
don't play it in a "romantic style" though, this is what is assessed in lists B/C (depending on your choices here). i.e. rubato and exaggerated dynamics and sentimentalism would be a little out of place here. "forte" means something different to scarlatti than it would to liszt or rachmaninov.
so forget the legato pedalling just now and focus on clean, articulate fingerwork, good luck with the exam when it comes