Cloud of daggers fills one 5-foot square.
Neither of the options that you show are correct. The spell description states that it takes up:
a cube 5 feet on each side
Since one square is five feet by five feet, you can fill one square with the cloud. If you target the center of a grid cell, then the spell fills that entire grid cell.
Note that the spell does not have a 5 foot radius. "5-foot radius" and "a cube 5 feet on each side" are very different measurements. A spell with a 5 foot radius fills a circle 10 feet wide. A spell that fills a cube 5 feet on a side fills a square, and that square is only 5 feet wide.