Were Naaman and Ard the sons or the grandsons of Benjamin??

Were Naaman and Ard the sons or the grandsons of Benjamin?
They were the sons of Benjamin	They were the grandsons of Benjamin
Genesis 46:21 And the sons of Benjamin were Belah, and Becher, and Ashbel, Gera, and Naaman, Ehi, and Rosh, Muppim, and Huppim, and Ard.	Numbers 26:38-40 The sons of Benjamin ... Bela ... And the sons of Bela were Ard and Naaman.