Question Find a nearest position

Hi there!

I really want to know How to find next (nearest and should be) box position if I press Up button to move up, as this image if I stay at red circle and want to go to that boxes How to move this red circle to overlap that nearest box?

Thanks

 

Nearest center of a box to the center of the circle is trivial:

var distance = (circle.transform.position - box.transform.position).magnitude;

Do this for all boxes and remember the box that (so far) had the smalles distance.