As a general rule, I will always go for as much strength at CB as possible, so if I would play Mellberg and Legro in there and then try to figure out what to do with fullbacks.
If Poulsen is fit, I would play him CB and move Mellberg at RB.
If a CB makes a mistake, it will almost always lead to a chance. If a fullback makes a mistake, there is a better chance of the team managing to recover.
From right to left:
De Ceglie-Mellberg-Legrottaglie-Molinaro
or
Mellberg-Poulsen-Legrottagie-Molinaro