Final answer:
The sons of Welthow are allowed to be the special guests of Beowulf at the feast honoring the victory over Grendel because Welthow is the wife of Hrothgar, the king of the Germanic society.
Step-by-step explanation:
The BEST reason why the sons of Welthow are allowed to be the special guests of Beowulf at the feast honoring the victory over Grendel is because Welthow is the wife of Hrothgar, the king. Traditionally, in Germanic society, the sons of a noble couple are given special status and privileges. In this case, honoring Welthow by allowing her sons to be guests of Beowulf showcases her importance and the respect given to her by the community.