Final answer:
The b. Magyars were the nomadic Hungarian group that invaded the Frank's kingdom during the reign of Charles the Great's grandson.
Step-by-step explanation:
The pneumatic Hungarian group that invaded the Frank's kingdom as Charles the Great's grandson fought over their inheritance were the b. Magyars.
These nomadic raiders came from the steppes of central Asia and settled in what is today Hungary. They launched devastating raids for plunder into Germany towards the end of the ninth century. Their power was not broken until 955 when the German king Otto the Great defeated them at the Battle of Lechfeld.