Final answer:
The best explanation of the interaction between the watchman and Beowulf in the English old epic 'Beowulf' is that the watchman, upon meeting Beowulf, asks him to state his intentions and observes his noble demeanor.
Step-by-step explanation:
The best selection that explains the interaction between Beowulf and the watchman is option B: "The watchman requires that Beowulf announce his reason for docking and remarks on his honorable appearance". In the epic of Beowulf, when Beowulf and his men arrive on the shores of Denmark, they are confronted by a guard, the watchman, charged with defending the